Std10 Science EM 2
Std10 Science EM 2
Std10 Science EM 2
12
PERIODIC CLASSIFICATION
OF ELEMENTS
Have you ever visited a library? There are
thousands of books in a large library. If you
ask for a book in general, it is very difficult
to trace, whereas if you ask for a particular
book, the library staff can locate it very
easily. How is it possible? In a library, the
books are classified into various categories
and sub categories. They are arranged on
the shelves accordingly. Therefore locating
a book becomes very easy.
CHEMISTRY
192
12.2.1. D
escription of Modern or Long
Form of the Periodic Table
Long form of the periodic table is a chart
of elements in which the elements have
been arranged in the increasing order of
their atomic numbers. This table consists
of horizontal rows called periods and
vertical columns called groups.
MORE TO KNOW
Middle portion
Groups 3 to
12
Transition
Inner transition
elements f Block
elements d Block
Lanthanides
193
Actinides
CHAPTER 12
S
ixth period (Atomic number 55 to 86):
This is the longest period. It contains
32 elements (Ceasium to Radon).
This includes 8 normal elements,
10 transition elements and 14 inner
transition elements (Lanthanides).
12.3. CHARACTERISTICS OF
MODERN PERIODIC TABLE
T
he atomic size of the elements in a
period decreases from left to right.
In a period, the metallic character of
the element decreases, while their nonmetallic character increases.
V
ertical columns in the periodic table
starting from top to bottom are called
groups. There are 18 groups in the
periodic table.
F
irst group elements are called alkali
metals.
T
he elements present in 2 and 18 Groups
differ in atomic number by 8,8,18,18,32.
S
econd group elements are called
alkaline earth metals.
G
roups three to twelve are called
transition elements .
G
roup 1, 2 and 13 - 18 are called normal
elements or main group elements or
representative elements .
T
he elements present in a group have
the same valency.
CHEMISTRY
194
CHAPTER 12
195
12.3.3. Advantages of
Periodic Table
the
T
he table is based on a more fundamental
property ie., atomic number.
P
osition of hydrogen is not fixed till
now.
P
osition of Lanthanides and Actinides
has not been given inside the main body
of periodic table.
T
he completion of each period is more
logical. In a period, as the atomic
number increases, the energy shells
are gradually filled up until an inert gas
configuration is reached.
E
ach group is an independent group
and the idea of sub-groups has been
discarded.
O
ne position for all isotopes of an
element is justified, since the isotopes
have the same atomic number.
12.4. METALLURGY
T
he position of the eighth group (in
Mendeleevs table) is also justified in
this table. All transition elements have
been brought in the middle as the
properties of transition elements are
intermediate between left portion and
right portion elements of the periodic
table.
CHEMISTRY
T
he table completely separates metals
from non-metals. The non-metals are
present in upper right corners of the
periodic table.
T
he positions of certain elements which
were earlier misfit (interchanged) in the
Mendeleevs periodic table are now
justified because it is based on atomic
number of the elements.
J ustification has been offered for
placing lanthanides and actinides at
the bottom of the periodic table.
196
I ( Al ) am a light silvery
white metal used to build
aircraft. So, I am great.
I ( Cu ) am a reddish brown
metal used to mint coins.
So, I am great.
MORE TO KNOW
INTRODUCTION
Metals
like
titanium,
chromium,
manganese, zirconium etc. find their
applications in the manufacture of defence
equipments. These are called strategic
metals. The metal uranium plays a vital role
in nuclear reactions releasing enormous
energy called nuclear energy. Copper, silver
and gold are called coinage metals as they
are used in making coins, jewellery etc.
197
Aluminium foil
Gold Bangles
CHAPTER 12
MORE TO KNOW
The vitality of metals for the totality of life
Metals in minute amounts are essential for various biological purposes.
Fe a constituent of blood pigment (haemoglobin).
Ca - a constituent of bone and teeth.
Co - a constituent of vitamin B-12 .
Mg - constituent of chlorophyll.
METALS AROUND US
CHEMISTRY
Gold
Silver
198
Aluminium
Carbonate Ores
Marble (CaCO3)
Halide Ores
Cryolite (Na3AlF6)
Sulphide Ores
Galena (PbS)
Cuprite (Cu2O)
Magnesite (MgCO3)
Fluorspar (CaF2)
Zincite (ZnO)
Calamine (ZnCO3)
Hornsilver (AgCl)
Cinnabar (HgS)
Haematite (Fe2O3)
Siderite (FeCO3)
ORE
Metals of high
reactivity
Electrolytic reduction,
Refining
Pure Metal
Metals of moderate
reactivity
Calcination, Roasting,
Reduction, Refining
Pure Metal
199
Metals of low
reactivity
Roasting,
Reduction, Refining
Pure Metal
CHAPTER 12
Concentrated ore
Symbol : Al
NaAlO2 + 2H2O
Colour : S
ilvery white
Atomic number : 13
Valency : 3
2Al(OH)3
Atomic mass : 27
Formula
Bauxite
Al2O3.2H2O
Cryolite
Na3AlF6
Corundum
Al2O3
NaOH + Al(OH)3
Electronic configuration:2, 8, 3
1000C
Al2O3 + 3H2O
CHEMISTRY
Sodium meta
aluminate
Temperature : 900-950C
Voltage used : 5-6V
200
Graphite rods
Graphite rods
Electrolyte
aluminium
Properties of Aluminium
Physical properties:
2.
Reaction with water: Water does not
react on aluminium due to the layer of
oxide on it. When steam is passed over
red hot aluminium, hydrogen is produced.
2Al + 3H2O
Steam
Al2O3 + 3H2
Aluminium
Oxide
3.
Reaction with alkalis: It reacts with
strong caustic alkalis forming aluminates.
2Al + 2NaOH + 2H2O
2NaAlO2 + 3H2
Sodium meta
aluminate
2Al + 6HCl
2AlCl3 + 3H2
Aluminium
Chloride
201
CHAPTER 12
4.
Reaction with acids: With dilute and
con. HCl it liberates H2 gas.
INDUSTRIAL VISIT
Aluminium
Sulphate
MORE TO KNOW
5. R
educing action : Aluminium is a
powerful reducing agent. When a mixture of
aluminium powder and iron oxide is ignited,
the latter is reduced to metal. This process
is known as aluminothermic process.
Symbol : Cu
Atomic mass : 63.55
Atomic number : 29
Electronic configuration : 2
, 8, 18, 1
Uses of Aluminium
USES
FORM
Fig 12.3
Valency : 1 and 2
REASON
1.Household
utensils
Aluminium
metal
It is light, cheap,
corrosion resistant, and
a good conductor of
heat.
2.Electrical
cable
industry
Aluminium
wires
It is a good conductor
of electricity.
3. Aeroplanes
and other
industrial
parts
Duralumin
Its alloys are light, have
Al,Cu,Mg,Mn
high tensile strength
Magnalium
and corrosion resistant.
Al,Mg
4.Thermite
welding
Al powder
and Fe2O3
Formula
CuFeS2
iii.Copper glance
Cu2S
CHEMISTRY
202
Iron silicate
203
(conc.)
CHAPTER 12
(conc.)
Cu + Cl2 CuCl2
v. Action of Alkalis: Copper is not attacked
by alkalis.
Uses of Copper:
It is extensively used in manufacturing
electric cables and other electric
appliances.
It is used for making utensils, containers,
calorimeters and coins.
It is used in electroplating.
It is alloyed with gold and silver for
making coins and jewels.
PROJECT
Submit a project report on the important
applications of copper in everyday life
Ores of iron
Formula
i.Haematite
Fe2O3
ii.Magnetite
Fe3O4
iii.Iron pyrite
FeS2
CHEMISTRY
Symbol: Fe
Colour: Greyish white
Atomic mass: 55.9
Atomic number: 26
Electronic configuration : 2, 8, 14, 2
Valency: 2 & 3
Occurrence:
C + O2 CO2 + heat
204
1000C
imestone decomposes
L
oxide and CO2.
to
MORE TO KNOW
400C
Hot gases
coke and
lime
Slag outlet
Chemical properties
Iron outlet
1.R
eaction with air or oxygen: Only on
heating in air, iron forms magnetic oxide.
3Fe + 2O2 Fe3O4 (black)
205
CHAPTER 12
Iron ore,
12.7 ALLOYS
An alloy is a homogeneous mixture of a
metal with other metals or with non-metals
that are fused together.
Alloys are solid solutions. Alloys can be
considered as solid solutions in which the
metal with high concentration is the solvent
and the metal with low concentration is the
solute. For example, brass is an alloy of
zinc(solute) in copper(solvent).
Fe + H2SO4 FeSO4 + H2
ith dilute HNO3 in cold condition it gives
W
ferrous nitrate.
4Fe + 10HNO34Fe(NO3)2 + NH4NO3 + 3H2O
MORE TO KNOW
DENTAL AMALGAMS
It is an alloy of mercury with silver and tin
metals. It is used in dental filling.
CHEMISTRY
Uses of Iron
i. P
ig iron is used in making pipes, stoves,
radiators, railings, manhole covers and
drain pipes.
ii. Steel is used in the construction of
buildings, machinery, transmission cables
and T.V. towers and in making alloys.
206
Dental amalgam
Uses
i.Brass(Cu,Zn)
ii.Bronze(Cu,Sn)
Uses
Aircraft,tools,
pressure cookers
ii.Magnalium(Al,Mg)
Uses
Utensils,cutlery,automobile
parts.
ii.Nickel steel
(Fe,C,Ni)
Hard, corrosion
resistant,elastic.
Cables,aircraft parts,propeller.
Water droplet
O2
12.8. CORROSION
Fe2+
Rust
IRON
Rusting of iron
MORE TO KNOW
When the surface of iron is exposed to moisture and other gases present in the
atmosphere, chemical reaction takes place.
_
O2 + 2H2O + 4e 4OH
The Fe2+ ions are oxidised to Fe3+ ions. The Fe3+ ions combine with OHions to form Fe(OH)3.This becomes rust (Fe2O3.xH2O) which is hydrated
ferric oxide.
207
CHAPTER 12
Fe Fe2+ + 2e
ACTIVITY 12.1
Take three test tubes provided with rubber corks and label them as A, B and C.
Place a few iron nails of the same size in these tubes. Pour some water in test tube
A, some boiled water along with turpentine oil in test tube B and anhydrous CaCl2 in
test tube C. Observe them for a few days. Notice the changes.
The nails in A get rusted, while the nails in B and C remain unaffected.
The rusting of the nails in test tube A is due to air and water. In B, the oily layer above
the water does not allow air to come in contact with the nails. In C, the substance
anhydrous CaCl2 has absorbed the moisture completely. This activity shows that
rusting of iron requires air and water.
CHEMISTRY
B
y coating with paints: Paint coated
metal surfaces keep out air and moisture.
B
y coating with oil and grease:
Application of oil and grease on the
surface of iron tools prevent them from
being acted upon by moisture and air.
B
y alloying with other metals: Alloyed
metals are more resistant to corrosion.
Example: stainless steel.
B
y the process of galvanization:
is a process of coating zinc on
sheets by using electric current. In
zinc forms a protective layer of
carbonate on the surface of iron.
prevents corrosion.
This
iron
this,
zinc
This
E
lectroplating: It is a method of coating
one metal with another by passing
electric current. Example: silver plating,
nickel plating. This method not only
protects but also enhances the metallic
appearance.
S
acrificial protection: Magnesium is
more reactive than iron. When it is coated
on the articles made of steel it sacrifices
itself to protect steel.
208
PART - B
1. Assertion: A greenish layer appears on copper vessels, if left uncleaned.
Reason: It is due to the formation of a layer of basic copper carbonate
Give the correct option:
i) Assertion and reason are correct and relevant to each other.
ii) Assertion is true but reason is not relevant to the assertion.
2.
A process employed for the concentration of sulphide ore is __________.
(froth floatation / gravity separation)
3. Coating the surface of iron with other metal prevents it from rusting. If it is coated with
a thin layer of zinc, it is called _______ . (galvanization / painting / cathodic protection)
4. Any metal mixed with mercury is called an amalgam. The amalgam used for dental
filling is _________. (Ag Sn amalgam / Cu Sn amalgam)
5. A
ssertion: In thermite welding, aluminium powder and Fe2O3 are used.
Reason: Aluminium powder is a strong reducing agent. Does the reason satisfy the
assertion?
7. Iron reacts with con. HCl and con. H2SO4 , but it does not react with con.HNO3. Justify
your answer with proper reasons.
8. To design the body of an aircraft, aluminium alloys are used. Give reasons.
9. X is a silvery white metal. X reacts with oxygen to form Y. The same compound is
obtained from the metal on reaction with steam with the liberation of hydrogen gas.
Identify X and Y.
209
CHAPTER 12
6. Can the rusting of iron nails occur in distilled water? Justify your answer.
L
G
O
L
D
O
O
A
K
M
P
P
A
D
B
C
A
N
H
Q
Z
I
L
T
L
P
A
R
Y
N
E
I
I
E
L
S
X
E
G
N
G
R
O
U
P
B
A
I
V
I
G
T
W
C
S
D
K
O
E
U
V
D
E
E
L
D
N
E
O
N
S
S
CLUES:
DOWN
ACROSS
a. vertical columns are called _____ a. horizontal rows are called _____
b. second group elements are
named as _____earth metals.
CHEMISTRY
Step1
Step2
Step 3
Step 4
Step 5
Al
Cu
Fe
210
Ore
Chemical formula
Reduction process
Al
Cu
haemetite
bauxite
PbS
Fe2O3
blast furnace
bessemerisation
Fe
copper pyrite
Al2O3 . 2H2O
froth floatation
Pb
galena
CuFeS2
Halls process
14. Here are a few statements related to alloys. Identify the incorrect ones and correct
them.
i) It is a homogenous mixture of metals.
ii) Zinc amalgam is used in dental filling.
iii) Duralumin is used for making statues, coins, bells and gongs.
iv) Alloys are produced by compressing finely divided metals one over the other.
v) Zinc is the solvent of brass.
15. Complete the following table:
Zone
Combustion zone
Temperature
400C
Chemical Process
CaCO3
CaO+CO2
CaO+SiO2
CaSiO3
211
CHAPTER 12
Type of iron
Percentage of Carbon
Uses
steel
2 4.5 %
wrought iron
pig iron
0.25 2 %
< 0.25%
PART - C
1. Redraw and label the diagram. Then answer the following questions.
CHEMISTRY
1. Why cannot aluminium metal be obtained by the reduction of aluminium oxide with
coke?
FURTHER REFERENCE
Books: 1. Text Book of Inorganic chemistry P.L. Soni S.Chand Publishers, New Delhi
Webliography: www.tutorvista.com.
science.howstuffworks.com
212
Chapter10
13
Atomic Number :
Atomic Mass
12
Valency
Group
14
INTRODUCTION
Without carbon, no living thing could
survive. Human beings are made up of
carbon compounds. Carbon is a non-metal.
In nature, it occurs in its pure form as
diamond and graphite. When fuels burn,
the carbon in them reacts with oxygen to
form carbon dioxide.
213
LIVING CHEMISTRY
All living organisms are made of carbon atoms. This means that, carbon atoms form the
building blocks of living organisms. These carbon atoms, in combination with other atoms
decide life on earth. Hence carbon chemistry is also called as living chemistry.
Fig. 13.3
Fig. 13.4
FRIEDRICH WOHLER
A creator of revolution in ORGANIC CHEMISTRY
ORGANIC CHEMISTRY:
MORE TO KNOW
CHEMISTRY
214
FRIEDRICH WOHLER
A German Chemist
A polished diamond
C
H
H
H
215
CHAPTER 13
13.4. ALLOTROPY
Allotropy is defined as the property by
which an element can exist in more than
one form that are physically different but
chemically similar.
Allotropes of carbon
Carbon exists in three allotropic forms.
They are: crystalline form (diamond
and
graphite),
amorphous
form
(coke,charcoal) and fullerene.
CHEMISTRY
216
e.g.
CH2 = CH 2
Ethene
H2
Ni-catalyst
CH3 - CH3
Ethane
Carbon
compounds
suchas
alcohols react with sodium to liberate
hydrogen gas.
Carbon
compounds
combustible.
easily
CH3COOH+ H2O
ethanoic acid
13.7.1. Characteristics of
Homologous series
Each member of the series differs
from the preceding or succeeding
member by a common difference of CH2
and by a molecular mass of 14 amu
( amu = atomic mass unit).
CH3CH2OH
ethanol
Unsaturated
carbon
compounds
Alkene = CnH2n
undergo
addition
reactions
with
hydrogen in the presence of palladium
Alkyne = CnH2n - 2
or nickel catalyst.
217
CHAPTER 13
are
13.8. IMPORTANCE OF
HOMOLOGOUS SERIES
1. It helps to predict the properties of the
members of the series that are yet to be
prepared.
Common
name
IUPAC
name
CH4
Methane
Methane
CH3CH3
Ethane
Ethane
CH3CH2CH3
Propane
Propane
CH3CH2CH2CH3
n-Butane
Butane
CHEMISTRY
13.9.1.
Saturated
Alkanes
Hydrocarbons
the corresponding
For example,
CH3 CH3
ethane
alkane
by
-ene.
H2C = CH2
ethene
218
IUPAC Name
Ethylene
Ethene
CH3CH = CH2
Propylene
Propene
CH3CH2CH=CH2
-Butylene
But1ene
CH3CH = CHCH3
-Butylene
But2ene
ii) Alkynes: G
eneral formula: CnH2n-2
Suffix : -yne
The hydrocarbons containing carbon
to carbon triple bond are called alkynes.
Alkynes are named in the same way as
alkenes i.e., by replacing suffix -ane of alkane
with -yne. In higher members, the position
of triple bond is indicated by giving numbers
1, 2, 3, 4, .to the carbon atom in the
molecule.
Alkyne
Common Name
IUPAC Name
HC CH
Acetylene
Ethyne
H3C C CH
Methyl acetylene
Propyne
H3C C C CH3
Dimethyl acetylene
2-Butyne
H3C - CH2 C CH
Ethyl acetylene
1-Butyne
=> Alcohol
=> Aldehyde
=> Ketone
=> Carboxylic acid
Common Name
IUPAC Name
CH3OH
Methyl alcohol
Methanol
CH3-CH2-OH
Ethyl alcohol
Ethanol
CH3- CH2-CH2-OH
n-Propyl alcohol
1-Propanol
CH3-CH-CH3
OH
Isopropyl alcohol(or)
2-Propanol
secondary propyl
alcohol
CH3-CH2-CH2-CH2-OH
n-Butyl alcohol
1-Butanol
CH3-CH-CH2-OH
Isobutyl alcohol
2-Methyl1-propanol
CH3
2. Aldehydes
Molecular
Formula
Common Name
IUPAC
Name
HCHO
Formaldehyde
Methanal
CH3- CHO
Acetaldehyde
Ethanal
Propionaldehyde
Propanal
n-Butyraldehyde
Butanal
219
CHAPTER 13
Alkene
CH2 = CH2
13.10.1. Classification
of
organic
compounds
based
on
functional group
1. Alcohols
Alcohols are carbon compounds
containing OH group attached to alkyl
group. The general formula of alcohol is
R-OH where R is an alkyl group and OH
is the functional group. The IUPAC name
of alcohol is derived by replacing e, in the
word alkane, with the suffix ol. Hence we
get the name alkanol.
3. Ketones
Ketones
are
carbon
compounds
containing carbonyl CO group attached
to two alkyl groups. The general formula
of ketone is R-CO-R where R and R are
alkyl groups and CO is the functional
group. The IUPAC name of ketone is
derived by replacing e, in the word alkane,
with the suffix -one. Hence we get the name
alkanone.
Molecular Formula
Common Name
IUPAC Name
CH3COCH3
Dimethyl ketone
(Acetone)
Propanone
CH3COCH2CH3
Ethyl methyl
Butanone
ketone
CH3CH2COCH2CH3 Diethyl ketone
3-Pentanone
of
Ethanol
from
4. Carboxylic Acids
IUPAC
Name
HCOOH
Formic acid
Methanoic
acid
CH3-COOH
Acetic acid
Ethanoic
acid
CH3- CH2-COOH
CH3- CH2-CH2-COOH
n-Butyric acid
CHEMISTRY
Molecular Formula
Butanoic
acid
220
invertase
zymase
C6H12O6 + C6H12O6
Glucose Fructose
Sucrose
C6H12O6
2C2H5OH + 2CO2
Ethanol
Glucose
CH3CH2OH
Ethanol
FERMENTATION :
The slow chemical change that takes
place in complex organic compounds
by the action of enzymes leading to the
formation of simple molecules is called
fermentation.
Conc.H2SO4
443K
CH2=CH2+H2O
Ethene
(b)
Inter molecular dehydration : When
excess of ethanol is heated with conc.
H2SO4 at 413K, it undergoes inter
molecular dehydration. (i.e. removal of
water from two molecules of ethanol)
to give diethyl ether.
C2H5- OH + HO- C2H5
Conc.H2SO4
413K
C2H5-O-C2H5+H2O
Diethyl ether
2C2H5ONa + H2
sodium ethoxide
(iii) O
xidation : Ethanol is oxidized to
ethanoic acid with alkaline KMnO4 or
acidified K2Cr2O7
2[O]
CH3CH2OH
CH3COOH +H2O
K2Cr2O7 / H+ Ethanoic acid
During this reaction, the orange colour of
K2Cr2O7 changes to green. Therefore, this
reaction can be used for the identification
of alcohols.
221
CHAPTER 13
conc.H2SO4
Ethanoic acid
CH3COOC2H5 + H2O
Ethyl ethanoate
CH3CH2OH
Ethanol
Cu
573 K
CH3CHO+H2
Acetaldehyde
4. Uses
Ethanol is used
CHEMISTRY
1. a
s an anti-freeze in automobile
radiators.
2.
as a preservative for biological
specimen.
3. as an antiseptic to sterilize wounds, in
hospitals.
4.
as a solvent for drugs, oils, fats,
perfumes, dyes, etc.
I
t causes mental
emotional disorder.
depression
and
222
(iii)
Reaction
with
bicarbonates.
(CH3COO)2 Zn + H2
2CH3COONa + H2
carbonates
and
2CH3COOH + Na2CO3
CH3COOH + NaHCO3
CH3COONa + H2O
(v) D
ecarboxylation (Removal of CO2) :
When sodium salt of ethanoic acid is
heated with soda lime (solid mixure of
3 parts of NaOH and 1 part of CaO)
methane gas is formed.
CH3COONa
NaOH / CaO
CH4 + Na2CO3
4. USES
Ethanoic acid is used
1. For making vinegar which is used as a
preservative in food and fruit juices.
2. As a laboratory reagent.
3. For coagulating rubber from latex.
4. In the preparation of dyes, perfumes and
medicines.
MODEL EVALUATION
PART - A
223
CHAPTER 13
1. A
ssertion: Chemical bonds in organic compounds are covalent in nature.
Reason: Covalent bond is formed by the sharing of electrons in the bonding atoms.
Does the reason satisfy the given assertion?
It is due to the
6. The formula of methane is CH4 and its succeeding member ethane is expressed as
C2H6. The common difference of succession between them is _______ .(CH2 / C2 H2)
7. IUPAC name of the first member of alkyne is ___________ . (ethene / ethyne)
8. Out of ketonic and aldehydic group, which is the terminal functional group?
9. A
cetic acid is heated with Na2CO3 in a test tube. A colourless and odourless gas (X) is
evolved. The gas turns lime water milky. Identify X.
10. Assertion: Denaturation of ethyl alcohol makes it unfit for drinking purpose.
Reason: Denaturation of ethyl alcohol is carried out by pyridine.
Check whether the reason is correct for assertion.
PART - B
1. Write down the possible isomers and give their IUPAC names using the formula C4H10.
2. Diamond is the hardest allotrope of Carbon. Give reason for its hardness.
3. A
n organic compound (A) is widely used as a preservative in pickle and has a molecular
formula C2H4O2. This compound reacts with ethanol to form a sweet smelling compound
(B).
(i) Identify the compounds A and B.
(ii) Name the process and write the corresponding chemical equation.
4. An organic compound (A) of molecular formula C2H6O on oxidation with alkaline KMnO4
solution gives an acid (B) with the same number of carbon atoms. Compound A is used
as an antiseptic to sterilize wounds, in hospitals. Identify A and B. Write the chemical
equation involved in the formation of B from A.
5. C2H6O is the molecular formula for two compounds A and B. They have different
structural formula.
i) What is this phenomenon known as?
CHEMISTRY
224
PART - C
No.
Alkane
Alkene
Alkyne
1.
C2 H6 ethane
______ethene
C2 H2 ethyne
2.
______Propane
C3 H6 Propene
______propyne
3.
C4 H10 Butane
______Butene
______Butyne
225
CHAPTER 13
ii) CH3COCH3
iv)
CH3COOH
v) HCHO
4.
CHEMISTRY
iii) What is the product formed? What happens when this gas is passed through
bromine water?
iv) When ethanol vapour is passed through bromine water, why does no change occur?
226
Molecular Formula
CH3CH2CH2CH2OH
Common Name
IUPAC Name
Dimethyl ketone
Propanal
HCOOH
Butanone
8. Ethanoic acid is a member of Homologous series with general formula
CnH2n+1 COOH.
i) Name the series and give its functional group.
ii) Give the molecular formula and the common name of ethanoic acid.
iii) If this compound is mixed with ethanol in the presence of Conc.H2SO4 , a sweet
smelling compound is formed. Give the equation and name the compound.
iv) Ethanoic acid reacts with carbonates. Which gas is liberated during this reaction?
v) Write the balanced equation for the reaction of ethanoic acid with carbonate.
vi) Your grandmother has prepared mango pickle. What has she added to preserve it
for a long time?
9. i) Identify A & B.
B
4.5
%o
fw
ate
r
5%
ol
an
h
t
me
of
Ethanol
+
D
Denatured spirit
Power alcohol
ii) Convert ethanol into power alcohol. Mention one of its uses.
iii) What should be added to obtain denatured spirit?
10. Write a balanced equation using the correct symbols for these chemical reactions:
i) Action of hydrogen on ethene in the presence of nickel catalyst.
ii) Combustion of methane evolving carbondioxide and water.
iii) Dehydrogenation of ethanol.
iv) Decarboxylation of Sodium salt of ethanoic acid.
227
CHAPTER 13
11. Look at the picture and identify what happens. Support your answer with equations .
i) How is B formed from A ?
Ethanoic
acid
Ethanol
ii)
What happens when acetic acid is treated with carbonate salt. Name the gas
produced. What happens when this gas is treated with lime water?
Acetic acid
+
Carbonate salt
Lime water
iii) What happens when acetic acid is treated with ethanol in the presence of
concentrated H2SO4 ? Give the equation.
Ethanol
acetic acid
Conc. H2SO4
CHEMISTRY
12. Organic compounds A and B are the isomers with the molecular formula C2H6O.
Compound A produces hydrogen gas with sodium metal, whereas compound B
does not. Compound A reacts with acetic acid in the presence of concentrated H2SO4
to form compound C with a fruity flavour. What are the isomers A, B and the
compound C?
13. Organic compound A of molecular formula C2H6O liberates hydrogen gas with sodium
metal. A gives B of formula C4H10O, when it reacts with concentrated H2SO4 at
413K. At 443K with concentrated H2SO4 A gives compound C of formula C2H4. This
compound C decolourises bromine water. What are A, B and C?
14. Organic compound A of molecular formula C2H4O2 gives brisk effervescence with
sodium bicarbonate solution. Sodium salt of A on treatment with soda lime gives a
hydrocarbon B of molecular mass 16. It belongs to the first member of the alkane
family. What are A and Band how will you prepare A from ethanol?
FURTHER REFERENCE
Books: 1
.Organic chemistry - B.S. Bahl & Arun Bahl S.Chand Publishers, New Delhi.
2.Organic chemistry - R.T. Morrision & R.N. Boyd - Prentice Hall Publishers,
New Delhi.
3. Complete Chemistry(IGCSE) - Oxford University press, New York
Webliography: www.tutorvista.com,
www.topperlearning.com
228
Chapter 14
MEASURING INSTRUMENTS
Physics is the most basic science, which
deals with the study of nature and natural
phenomena. It is a science of measurement.
The ultimate test of any physical quantity
is its agreement with observations and
measurement of physical phenomena. One
of the major contributions of physics to
other sciences and society are the various
measuring instruments and techniques
that physics has developed. One such
instrument is the screw gauge.
S1
Milled Head
Pitch Scale
U-Shaped Frame
Index line
Head Scale
Fig 14.1
229
Safety device
(Ratchat)
Z.E = + (n x L.C),
= + (5 x L.C),
Pitch
No.of divisions on the head scale
Z.C = (5 x L.C)
Negative Zero Error
No Zero Error
Fig. 14.2
PHYSICS
230
Fig 14.4
Z.E = (100 5) x L.C,
and the Zero Correction
Z.C = + (100 5) x L.C
MEASURING INSTRUMENTS
To measure the diameter of a thin wire
using Screw Gauge
Determine the Pitch, the Least Count
and the Zero Error of the Screw Gauge.
Place the wire between the two studs.
Rotate the head until the wire is held
firmly but not tightly, with the help of
ratchet.
Note the reading on the pitch scale
crossed by the head scale (PSR) and
the head scale division that coincides
with the pitch scale axis (H.S.C).
The diameter of the wire is given by
P.S.R + (H.S.C x L.C) Z.C
Repeat the experiment for different
portions of the wire.
Tabulate the readings.
T he average of the last column
reading gives the diameter of the
wire.
S. P.S.R H.S.C
No. (mm) (division)
1
2
H.S.C
x L.C
(mm)
Total Reading
P.S.R +
(H.S.C x L.C)
Z.C (mm)
MODEL EVALUATION
1. Screw Gauge is an instrument used to measure the dimensions of very small objects
upto
(0.1 cm, 0.01 cm, 0.1 mm, 0.01 mm)
2. In a Screw Gauge, if the zero of the head scale lies below the pitch scale axis, the zero
error is
.(positive, negative, nil)
3.
The Screw Gauge is used to measure the diameter of a
(crowbar, thin wire, cricket ball )
231
CHAPTER 14
PART - A
i) 365.25 x 24 x 60 x 60 x 3 x 108 m
ii) 1x 24 x 60 x 60 x 3 x 108 m
PART - B
1. Correct the mistakes if any, in the following statements:
i) Astronomical unit is the mean distance of the surface of the sun from the surface of
the earth.
ii) L
ight year is the distance travelled by light in one year in vacuum at a speed of
3x108 m per minute.
2. Match the items in group A with the items in group B:
Sl.No.
Group A
1.
11111111
2.
2.
11111111
3.
11111111
4.
11111111
Group B
Small dimensions
Large dimensions
Kilometre
Screw gauge
Long distance
Scale
Small distance
Light year
Altimeter
i) Head scale
PHYSICS
FURTHER REFERENCE
Webliography: www.tutorvista.com
science.howstuffworks.com
232
Chapter 15
Fig. 15.1
233
(a)
Name : Galileo
Born : 15th February 1564
Birth place : Grand Duchy of Tuscany, Italy
Died : 8th January 1642
Best known for : Astronomy, Physics
and Mathematics
(b)
(c)
PHYSICS
Fig. 15.2
234
15.4.MOMENTUM
ACTIVITY 15.1
Let us recall some observations from
our day-to-day life. During the game of
table tennis, if a ball hits a player, it does
not hurt him. On the other hand, when a
fast moving cricket ball hits a spectator,
Fig. 15.3.
it may hurt him. A truck at rest does not
require any attention when parked along
Make a pile of similar carrom coins on a roadside. But a moving truck, even at a
a table as shown in Fig.15.3. Attempt a very low speed, may kill a person standing
sharp horizontal hit at the bottom of the in its path. A small mass such as a bullet
pile using another carrom coin or the may kill a person when fired from a gun.
striker. If the hit is strong enough, the These observations suggest that the impact
bottom coin moves out quickly. Once the produced by an object depends on its mass
lowest coin is removed, the inertia of the and velocity. In other words, there appears
other coins makes them fall vertically on to exist some quantity that combines the
the table without disturbing the pile.
objects mass and velocity to produce an
impact. Such a quantity of motion was
called momentum by Isaac Newton. The
15.3. INERTIA AND MASS
momentum p of an object is defined as the
All the examples and activities given product of its mass m and velocity v.
so far, illustrate that there is a resistance
p = mv
235
CHAPTER 15
PHYSICS
F ma
F = k ma ...........(3)
F = ma ........... (4)
m (v-u)
= ...........(2)
t
Solution:
Given, mass of the object m = 10 kg
Initial velocity u = 2 m s-1
Final velocity v = 8 m s-1
236
m(v - u)
We know, force F =
t
10 (8-2) 10 6
F = = = 15 N
4
4
Example:15.2
Which would require a greater force for
accelerating a 2 kg of mass at 4 m s-2 or
a 3 kg mass at 2 m s-2?
Solution
We know, force
F = ma
Given m1 = 2 kg
a1 = 4 m s-2
m2 = 3 kg
a2 = 2 m s-2
Accelerating force
on the bullet
F1 = m1 a1 = 2 4 = 8 N
and F2 = m2 a2 = 3 2 = 6 N
~ F1 > F2
Fig. 15.5
15.7.CONSERVATION OF MOMENTUM
The law of conservation of momentum
states that, in the absence of external
unbalanced force, the total momentum of a
system of objects remains unchanged.
Fig. 15.4
237
CHAPTER 15
Proof:
m2 (v2 u2)
= m1 (v1-u1)
During collision
ACTIVITY 15.2
T
ake a big rubber balloon and inflate it
fully.Tie its neck using a thread. Also,
fix a straw on the surface of this balloon
using adhesive tape.
(C)
After collision
Fig. 15.6
P
ass a thread through the straw and
hold one end of the thread in your hand
or fix it on the wall.
A
sk your friend to hold the other end
of the thread or fix it on a wall at some
distance.
This arrangement is shown in Fig.15.7
N
ow, remove the thread tied on the
neck of the balloon. Let the air escape
through the mouth of the balloon.
m1 (v1-u1)
F2 =
..... (2)
t
STRAW
PHYSICS
m2 (v2-u2)
m1 (v1-u1)
=
t
t
BALLOON
Fig. 15.7
238
T = Fd
= 1.5 + 2v2
Fig. 15.8
1.5 + 2v2 = 0
2v2 = - 1.5
Distance d
Moment of force = F x d.
v2 = - 0.75 m s-1
239
CHAPTER 15
P Force
F2
Fig. 15.9.
As a matter of convention, an
anticlockwise moment is taken as positive
and a clockwise moment as negative.
Couple
There are many examples in practice
where two forces, acting together, exert a
moment or turning effect on some object.
As a very simple case, two strings are tied
to a wheel at the points X and Y, and two
equal and opposite forces, F are exerted
tangentially to the wheels (Fig. 15.10). If the
wheel is pivoted at its centre O it begins to
rotate about O in an anti-clockwise direction.
90
Y
90
Fig. 15.10
PHYSICS
15.9. GRAVITATION
240
Fig. 15.11
Weight, W = m g
........(1)
........(2)
m1m2
F ........(3)
d2
Mass
(or)
G m1m2
F = ........(4)
d2
where G is the constant of proportionality
and is called the universal gravitational
constant. From equation (4)
W = 5 9.8 = 49 N
Mass, m = 5 kg
Acceleration due to gravity, g = 9.8 m s-2
F.d2
G =
m1 m2
15.9.2. Mass
Mass is the quantity of matter contained
in a body.
15.9.3. Weight
Weight is the gravitational force acting
on a body. It is a measure of how strongly
gravity pulls on that body.
If you were to travel to the moon, your
weight would change because the pull of
gravity is weaker there than that on the
earth, but your mass would stay the same
because you are still made up of the same
amount of matter.
Example: 15.4
The mass of an object is 5 kg. What is its
weight on the earth?
Weight
1. Fundamental
quantity.
Derived quantity.
It is the
gravitational pull
acting on the
body.
3. Its unit is
kilogram.
Its unit is
newton.
4. Remains the
same.
Varies from
place to place.
5. It is measured
using physical
balance.
It is measured
using spring
balance.
241
CHAPTER 15
F m1m2
1
F
d2
Solution:
mg
M = 6.67
10-11
M = 5.98 1024 kg.
Science Today
Earth
Fig.15.12
Its distance from the centre of the Earth
is R (radius of the Earth).
PHYSICS
GM
g =
R2
R2
where M is the mass of the earth.
Force, F = mg
Chandrayaan
Chandrayaan-1 is a moon-traveller or
moon vehicle. It was Indias first unmanned
lunar probe. It was launched by the Indian
Space
Research
Organization(ISRO)
in October 2008 from Srihari Kota in
Andrapradesh and operated until August
2009. The mission included a lunar orbiter
and an impactor. It carried five ISRO
payloads and six payloads from other space
agencies including National Aeronautics
and
Space Administration
(NASA),
European Space Agencies(ESA), and the
Bulgarian Aerospace Agency(BAA), which
were carried free of cost.
242
T
he discovery of wide-spread presence
of water molecules in lunar soil.
C
handrayaans
Moon
Mineralogy
Mapper has confirmed that moon was
once completely molten.
E
uropean Space Agency payloadChandrayaan-1
imaging
X-ray
spectrometer (CIXS) detected more than
two dozen weak solar flares during the
mission.
The
terrain mapping camera on board
Chandrayaan-1 has recorded images
of the landing site of the US space-craft
Apollo-15, Apollo-11.
It has provided high-resolution spectral
data on the mineralogy of the moon.
L
unar Laser Ranging Instrument (LLRI)
covered both the Lunar Poles and
additional lunar region of interest.
T
he X-ray signatures of aluminium,
magnesium and silicon were picked up
by the CIXS X-ray camera.
T
he Bulgarian payload called Radiation
Dose Monitor (RADOM) was activated
243
CHAPTER 15
PHYSICS
244
(v) Vaccines:
The freezing of biotechnology products
like vaccines require nitrogen freezing
system.
Space Station:
A space station is an artificial structure
designed for humans to live and work in the
outer space for a certain period of time.
Modern and recent-history space stations
are designed to enable stay in the orbit,
for a span of few weeks, months or even
years. The only space stations launched for
this specific purpose are Almaz and Salyut
Series, Sky lab and Mir.
245
CHAPTER 15
In future the space, as human habitat, is expected to address these issues, and made
suitable for long-term occupation. Some designs might even accommodate a large number
of people, essentially cities in space where people would make their homes. No such
design has yet been constructed, even for a small station. The cost of the latest(2010)
launch is not economically or politically viable.
The Peoples Republic of China launched its space station named
Tiangong 1, in the first half of 2011. This declared China the third country to launch a
space station.
MODEL EVALUATION
PART A
1. The acceleration in a body is due to ___________.
i) balanced force
ii) acceleration
iii) force
iv) impulse
iii) zero
iv) infinity
4. The mass of a person is 50 kg. The weight of that person on the surface of the earth will
be ________.i) 50 N
ii) 35 N
iii) 380 N
iv) 490 N
5. T
he freezing of biotechnology products like vaccines require ________ freezing system.
i) Helium
ii) Nitrogen
iii) Ammonia
iv) Chlorine
6. Two objects of same mass, namely A and B hit a man with a speed of 20 km/hr and
50 km/hr respectively and comes to rest instantaneously. Which object will exert more
force on that man? Justify your answer.
7. An object is moving with a velocity of 20 m/s. A force of 10 N is acting in a direction
perpendicular to its velocity. What will be the speed of the object after 10 seconds?
8. Assertion(A) : Liquefied cryogenic gases are sprayed on electric cables in big cities.
Reason(R): Liquefied cryogenic gases prevent wastage of power.
i) A is incorrect and R is correct.
PHYSICS
9. The acceleration due to gravity on the surface of the earth will be maximum at ________
and minimum at _________
10. If the radius of the earth is reduced to half of its present value, with no change in the
mass, how will the acceleration due to gravity, be affected?
11. Selvi placed her purse on the passengers seat of her car when she drove to work.
By the time she reached her office, her purse had fallen on the floor in front of the
passengers seat. Why did this happen? Explain.
246
PART B
1. Fill in the blanks.
i) If force = mass x acceleration, then momentum = __________.
ii) If liquid hydrogen is for rocket, then is for MRI.
2. Correct the mistakes, if any, in the following statements.
i) One newton is the force that produces an acceleration of 1 ms-2 in an object of 1 gram
mass.
ii) Action and reaction always act on the same body.
3. The important use of cryogenics is cryogenic fuels. What do you mean by cryogenic
fuels?
4. As a matter of convention, an anticlockwise moment is taken as ________ and a clockwise
moment is taken as ________.
5. A bullet of mass 20 g moving with a speed of 75 ms-1 hits a fixed wooden plank and
comes to rest after penetrating a distance of 5 cm. What is the average resistive force
exerted by the wooden plank on the bullet?
6. A shopping cart has a mass of 65 kg. In order to accelerate the cart by 0.3ms-2 what
force would you exert on it?
7. Why does a spanner have a long handle?
8. Why does a boxer always move along the direction of the punch of the opponent?
9. The mats used in gyms and the padding used in sports uniforms are made up of soft
substances. Why are rigid materials not used?
11. A 10 Kg mass is suspended from a beam 1.2 m long. The beam is fixed to a wall. Find
the magnitude and direction (clockwise or anti-clockwise) of the resulting moment at
point B.
1.2m
B
10Kg
247
CHAPTER 15
12. If the force experienced by a body of unit mass is gravitational field strength, find the
gravitational field strength on the surface of the earth.
13. If the density of the earth is doubled to that of its original value, the radius remaining
the same, what will be the change in acceleration due to gravity?
14. Renu is standing in a dining line 6.38 x 103 km from the centre of the earth. The mass
of the earth is 6 x 1024 kg.
i) Find the acceleration due to gravity.
ii) Will the value change after she finishes her lunch?
15. If an angel visits an asteroid called B 612 which has a radius of 20 m and mass of
104 kg, what will be the acceleration due to gravity in B 612 ?.
16. A man of mass m standing on a plank of mass M which is placed on a smooth
horizontal surface, is initially at rest. The man suddenly starts running on the plank
with a speed of v m/s with respect to the ground. Find the speed of the plank with
respect to the ground.
17. Two balls of masses in ratio 2:1 are dropped from the same height. Neglecting air
resistance, find the ratio of
i) the time taken for them to reach the ground.
ii) the forces acting on them during motion.
iii) their velocities when they strike the ground.
iv) their acceleration when they strike the ground.
18. An object of mass 1 kg is dropped from a height of 20 m. It hits the ground and
rebounds with the same speed. Find the change in momentum.(Take g=10 m/s2)
19. What will be the acceleration due to gravity on the surface of the moon, if its radius is
1/4th the radius of the earth and its mass is 1/80 times the mass of the earth.
20. A boy weighing 20 kg is sitting at one end of a see-saw at a distance of 1.2 m from
the centre. Where should a man weighing 60 kg sit on the see-saw, so that it stands
balanced?
PHYSICS
1.2m
21. A cart driver prods his horse to move forward. The horse refuses to budge and explains:
According to Newtons III Law, I am pulling the cart, with a certain force and
the cart, in turn pulls me back with an equal amount of force. As they are equal in
magnitude and act in opposite directions, they cancel each other.
Do you agree with the explanation given by the horse? Support your answer with
proper reasons.
248
ii)
The figure represents two bodies of masses 10 kg and 15 kg, moving with an initial
velocity of 10 ms-1 and 5 ms-1 respectively. They collide with each other. After collision,
they move with velocities 4 ms-1 and 9 ms-1 respectively. The time of collision is 2 s.
Now calculate F1 and F2.
1
FF21
m/s F51 m/sF52 Fm/s
5 m/s
10 m/s 10 m/s10
10 Kg
15
10 Kg20 Kg10 Kg
20 Kg20
10 Kg
10Kg
Kg
20 kg
Kg
F2
m/s
12m/s 12m/s412m/s
9 m/s
4m/s 4m/s 4m/s
15
kg
kg
10
Kg
10 Kg 20 Kg 15
20 Kg
20
Kg
10 Kg
10
Kg 20 Kg
20 Kg
2. College Physics by : R.L.Weber, K.V. Manning, Tata McGraw Hill, New Delhi.
3. P
rinciples of Physics(Extended) - Halliday, Resnick & Walker,
Wiley publication, New Delhi.
Webliography: www.khanacademy.org
249
science.howstuffworks.com
CHAPTER 15
FURTHER REFERENCE
Chapter 16
ELECTRICITY AND
ENERGY
Name
: Michael Faraday
Born
PHYSICS
Q
t
250
t = 1s,
then I = 1A.
I = 0.75 A,
t = 10 minutes = 600 s
We know,
Q=It
= 0.75 600
Q = 450 C
Bulb
16.2. E
LECTRIC
POTENTIAL
POTENTIAL DIFFERENCE
AND
251
CHAPTER 16
SYMBOLS
The
amount
of
in moving the charge,
work
done
W=VQ
W= 10 5
W= 50 J
An electric cell
A battery or a
combination of
cells
Plug key or
switch (open)
Plug key or
switch (closed)
Name
Born
Birth place
: Erlangen, Germany
Died
A wire joint
Wires crossing
without joining
Electric bulb
A resistor of
resistance R
ACTIVITY 16.1
S
et up a circuit as shown in
Fig. 16.2. consisting of a nichrome
wire XY of length 0.5m, an ammeter, a
Voltmeter and four cells of 1.5V each.
(Nichrome is an alloy of Nickel and
Chromium).
Variable
resistance or
rheostat
Ammeter
F
irst use only one cell as the source in
the circuit.
Voltmeter
Light Emitting
N
ote the reading in the ammeter I
for the current and reading of the
voltmeter V for the potential difference
across the nichrome wire XY in the
circuit.
Diode
Table 16.1.
PHYSICS
Example 16.2.
How much work is done in moving a
charge of 5 C across two points having a
potential difference 10 V ?
Solution:
Given charge Q = 5 C
Potential difference V = 10 V
252
S.
No.
Number of
cells used in
the circuit
Potential difference
across the nichrome
wire. V (volt)
R=V/I
(volt/ampere)
(ohm)
1.
2.
3.
4.
5.
6.
Example 16.3
The potential difference between the
terminals of an electric heater is 60 V when
it draws a current of 5 A from the source.
What current will the heater draw if the
potential difference is increased to 120 V ?
Solution:
V = IR
253
Potential difference, V = 60 V
Current,
I=5A
CHAPTER 16
Fig. 16.2
I = V / R = 120 / 12 = 10 A
S
et up the circuit by connecting four
dry cells of 1.5 V each in series with
the ammeter leaving a gap XY in the
circuit, as shown in Fig. 16.3.
Fig. 16.4
C
omplete the circuit by connecting
the nichrome wire in the gap XY.
Plug the key. Note down the ammeter
reading. Take out the key from the
plug.
R
eplace the nichrome wire with the
torch bulb in the circuit and find the
current through it by measuring the
reading of the ammeter.
V = V1+V2+V3
(1)
N
ow repeat the above steps with the
LED bulb in the gap XY.
V1 = IR1,
V2 = IR2,
V3 = IR3
D
o the ammeter readings differ for
various components connected in
the gap XY? What do the above
observations indicate?
V = IR1+IR2+IR3
Fig. 16.3
PHYSICS
254
R2 = 6
R1 + R2
RS = 18 + 6 = 24
(b) The potential difference V = 6 V
6
= 24
RS
I = 0.25 A
Fig. 16.5
Resistors in Parallel
Consider three resistors having resistances
R1, R2, R3 connected in parallel. This
combination is connected with a battery
and plug key as shown in Fig. 16.5
In parallel combination the potential
difference (V) across each resistor is the
same.
The total current I is equal to the sum of
the current through each resistor.
I = I1+I2+I3
(1)
I1 =
I2 =
R1
I3 =
R2
V
R3
I=
R1
R2
R3
V
R1
1
R1
V
R2
1
R2
V
R3
1
R3
Given, R1 = 5 , R2 = 10 , R3 = 30
These resistances are connected parallel
Therefore, 1 / Rp = 1 / R1 + 1 / R2 + 1 / R3
1 1 1 1 10
= + + =
Rp 5
10
30
30
30
Rp = = 3
10
16.7. H
EATING EFFECT OF
ELECTRIC CURRENT
We know that a battery is a source of
electrical energy. Its potential difference
between the two terminals sets the
electrons in motion for the current to flow
through the resistor.
255
CHAPTER 16
I=
T
ake an electric cell, a bulb, a switch
and connecting wires. Make an
electric circuit as shown in Fig. 16.6.
By pressing the key allow the current
to pass through the bulb.
T
he bulb gets heated when current
flows continuously for a long time
(when the key is on).
H = W = VQ
since, Q = It
H=VIt
Applying Ohms law we get H = I Rt.
This is known as Joules law of
heating. The law implies that heat produced
in a resistor is
(1)directly proportional to the square of
current (I) for a given resistance,
PHYSICS
Fig. 16.6
A part of the energy may be consumed in
useful work (like in rotating the blades of
the fan). The rest of the energy may be
expended in heat to raise the temperature
of the gadget. If the electric circuit is
purely resistive, the energy of the source
continuously gets dissipated entirely in
the form of heat. This is known as heating
effect of electric current. Heating effect of
electric current is used in many appliances.
The electric iron, electric toaster, electric
oven and electric heater are some of the
familiar devices which uses this effect.
16.8. JOULES LAW OF HEATING
Consider a current I flowing through
a resistor of resistance R. Let the
(2)
directly proportional to the resistance
(R) for a given current,
(3)
directly proportional to the time(t) for
which the current flows through the
resistor.
Example 16.6
A potential difference 20 V is applied
across a 4 resistor. Find the amount of
heat produced in one second.
Solution:
Given potential difference, V = 20 V
The resistance,
R=4
The time,
t =1s
V
I =
R
256
H = I2Rt
H = 52 4 1 = 100 J
16.9. ROLE OF FUSE
A common application of Joules
heating is the fuse used in electric
circuits. It consists of a piece of wire
made up of an alloy (37% Lead, 63% Tin).
It has high resistance and low melting point.
The fuse is connected in series with the
device. During the flow of high current, the
fuse wire melts and protects the circuits and
the appliances.
16.10.DOMESTIC ELECTRIC CIRCUITS
257
Fig. 16.7
Electric fuse
Live wire
Watt meter
Neutral wire
Earth wire
Distribution box
CHAPTER 16
Example 16.7
Solution:
V = 220 V, I = 0.50 A
The power of the bulb,
P = VI = 220 x 0.50 = 110 W
16.12. CHEMICAL EFFECT OF
ELECTRIC CURRENT
ACTIVITY 16.4
C
arefully take out the carbon rods
from two discarded cells.
C
lean their metal caps with sand
paper.
V
(or) P = IR = R
The SI unit of electric power is watt (W).
1 watt is the power consumed by a device
that carries 1 A of current when operated at
a potential difference of 1 V . Thus,
W
rap copper wire around the metal
caps of the carbon rods.
C
onnect these copper wires in series
with a battery and an LED.
D
ip the carbon rods into lemon juice
taken in a plastic or rubber bowl.
Does the bulb glow?
1 W = 1 volt 1 ampere = 1 V A
PHYSICS
258
Fig. 16.8
:
:
:
:
:
Alessandro Volta
18th February 1745
Como, Italy
5th March 1827
The Italian who built
the first battery
Electrochemical cell
The cells in which the electrical energy
is derived from the chemical action are
called electrochemical cells.
Voltaic cell consists of two electrodes,
one of copper and the other of zinc dipped
in a solution of dilute sulphuric acid in a
glass vessel. This is shown in Fig. 16.9.
SECONDARY
Primary Cell
Copper rod
Zinc rod
Dilute H2So4
Glass vessel
Fig. 16.9
AND
259
CHAPTER 16
Leclanche cell
A Leclanche cell consists of a glass
vessel which is filled with ammonium chloride
solution. Ammonium chloride solution acts
as an electrolyte. In it there stands a zinc
rod and porous pot containing a carbon rod
which is packed round with a mixture of
manganese dioxide and powdered carbon.
The carbon and zinc rods act as positive
and negative electrodes respectively.
At the zinc rod, the atoms get ionised
and pass into the solution as Zn++ ions.
This leaves the zinc rod with two electrons
more making it negatively charged. At the
same time, Ammonium chloride splits into
ammonia gas, two Hydrogen ions (2H+)
and two chloride ions (2Cl-). Zn++ ions and
2Cl- ions recombine to form zinc chloride.
The 2H+ ions migrate to the carbon rod
and make it positively charged. When the
carbon rod and zinc rod are connected by a
wire, the current flows from carbon to zinc
through the wire. The e.m.f of the cell is
about 1.5V.
PbO2
Pb
Carbon rod
Zinc rod
Porous pot
H2SO4
Glass/rubber
container
Ammonium
chloride solution
Mixture of Carbon and
Manganese dioxide
Glass vessel
Fig.16.10
PHYSICS
Fig. 16.11
Secondary Cells
The advantage of secondary cells is
that they are rechargeable. The chemical
reactions that take place in secondary cells
are reversible. The active materials that
260
16.15.1.
Conventional
Energy
Sources
of
1. Fossil Fuels
In ancient times wood was the most
common source of energy. The energy of
flowing water and wind was also used for
limited activities. Can you think of some
of these uses? The exploitation of coal
as a source of energy made the industrial
revolution possible. Industrialisation has
caused the global demand for energy to
grow at a tremendous rate. The growing
demand for energy was largely met by fossil
fuels like coal and petroleum. These fuels
were formed over millions of years ago and
there are only limited reserves. Fossil fuels
are a non-renewable source of energy. So
we need to conserve them. If we were to
continue consuming these sources at such
alarming rates, we would soon run out of
energy. In order to avoid this, alternate
source of energy have to be explored.
Burning fossil fuels has other
disadvantages like air pollution, acid rain
and production of green house gases.
2. Thermal Power Plant
Large amount of fossil fuels are burnt
everyday in power stations to heat up
water to produce steam which further runs
the turbine to generate electricity. The
transmission of electricity is more efficient
than transporting coal or petroleum over the
same distance. Therefore, many thermal
power plants are set up near coal or oil
fields. The term thermal power plant is used
since fuel is burnt to produce heat energy
which is converted into electrical energy.
261
CHAPTER 16
Dam
Transformer
Sluice
gates
to
Downstream
outlet
Turbine
ns
Dam
Storage
reservoir
Gas tank
Soil
Fig. 16.12
PHYSICS
Gas outlet
Slurry
Pe
Generator
ck
Power house
Manure
Soil
Outlet
Digester
Fig 16.13
16.15.2.
Non-conventional Sources of
Energy
Our life styles are changing. We use
machines to do more and more of our
262
Solar cell
panel
1. Solar Energy
The sun has been radiating an
enormous amount of energy at the present
rate for nearly 5 billion years and will
continue radiating at that rate for about 5
billion years more. Only a small part of solar
energy reaches the outer layer of the earths
atmosphere. Nearly half of it is absorbed
while passing through the atmosphere and
the rest reaches the earths surface.
A black surface absorbs more heat than
any other surface under identical conditions.
Solar cookers and solar water heaters use
this property in their working. Some solar
cookers achieve a higher temperature by
using mirrors to focus the rays of the sun.
Solar cookers are covered with a glass
plate.
T
ake two conical flasks and paint
one white and the other black. Fill
both with water.
P
lace the conical flask in direct
sunlight for half an hour to one hour.
Glass
vessel
T
ouch the conical flasks. Which one
is hotter? You could also measure the
temperature of the water in the two
conical flasks with a thermometer.
C
an you think of ways in which this
finding could be used in your day to
day life?
Mirror
Fig. 16.15
263
CHAPTER 16
ACTIVITY 16.5
Fig 16.14
ACTIVITY 16.6
S
tudy the structure and working of a
solar cooker or a solar water- heater,
particularly with regard to how it is
insulated and maximum heat absorption
is ensured.
D
esign and build a solar cooker or
water-heater using low-cost material
available and check the temperature
achieved in your solar system.
D
iscuss what would be the advantages
and limitations of using the solar cooker
or water-heater.
2. Wind Energy
The kinetic energy of the wind can be
used to do work. This energy was harnessed
by windmills in the past to do mechanical
work. For example, in a water-lifting pump,
the rotatory motion of windmill is utilized to
lift water from a well. Today, wind energy is
also used to generate electricity. A windmill
essentially consists of a structure similar to
ACTIVITY 16.7
F
ind out from your grand-parents or
other elders
(a) How did they go to school?
(b) How did they get water for their
daily needs when they were
young?
PHYSICS
Fig. 16.16
264
n1
Kr92
U235
92
36
Name
: Henry Becquerel
Born
: 15 December 1852
Birth place
: Paris, France
Died
: 25 August 1908
n1
n1
Ba141
56
th
n1
th
265
CHAPTER 16
PHYSICS
Hydrogen Bomb
A suitable assembly of deuteron
and triton is arranged at the sight of the
explosion of the atom bomb. Favourable
temperature initiates the fusion of lighter
nuclei in an uncontrolled manner. This
releases enormous amount of heat
energy.
m = 1 kg
Velocity of light,
c = 3108 m s-1
Energy produced,
E = mc2
E = 1(3108 )2
E = 9 1016J
266
The
radiation
exposure
is
measured by the unit called roentgen(R).
One roentgen is defined as the quantity of
radiation which produces 1.6 x 1012 pairs of
ion in 1 gram of air.
The safe limit for receiving radiation is
about 250 milli roentgen per week.
The following precautions are to
be taken by those, who are working in
radiation laboratories.
(i) Radioactive materials are to be kept in
thick-walled lead container.
(ii) Lead aprons and lead gloves are to be
used while working in hazardous area.
(iii) A small micro-film badge is to be always
worn by the person and checked
periodically for the safety limit of
radiation.
(iv)
Nuclear devices can be operated
using remote control system.
(v)
Clean up contamination in the work
area promptly.
SCIENCE TODAY
Fig. 16.18
2. Wave Energy
Similarly, the kinetic energy possessed
by huge waves near the sea-shore can be
trapped in a similar manner to generates
electricity. The waves are generated by
strong winds blowing across the sea.Wave
energy would be a viable proposition only
where waves are very strong.
A wide variety of devices have been
developed to trap wave energy for rotation
of turbine and production of electricity.
(Fig.16.19)
Air back in
Air out
1. Tidal Energy
267
Turbine
Generator
Wave
Direction
Fig. 16.19
CHAPTER 16
Ammonia vapours
Generator
Heat
exchanger
(evaporator)
Turbine
Heat
exchanger
(condenser)
Warm
sea water
Pump
Liquid ammonia
Cold sea
water
Fig. 16.20
Discharge
MODEL EVALUATION
PART - A
1. The potential difference required to pass a current 0.2 A in a wire of resistance 20
ohm is _________. i)100 V
ii) 4 V
iii) 0.01 V
iv) 40 V
2. Two electric bulbs have resistances in the ratio 1 : 2. If they are joined in series, the
energy consumed in these are in the ratio _________. (1 : 2, 2 : 1, 4 : 1, 1 : 1)
3. Kilowatt-hour is the unit of __________. i) potential difference
iii) electric energy
iv) charge
4. ________ surface absorbs more heat than any other surface under identical
conditions. i) White
ii) Rough
iii) Black
iv) Yellow
5. The atomic number of natural radioactive element is _________.
i) greater than 82
ii) less than 82
iii) not defined
iv) atleast 92
PHYSICS
6. Which one of the following statements does not represents Ohms law?
ii) potential
difference / current = constant
268
PART - B
1. Fill in the blanks
ii) Hydro power plant : Conventional source of energy; then solar energy: _________.
2. In the list of sources of energy given below, find out the odd one.
(wind energy, solar energy, hydro electric power)
3. Correct the mistakes, if any, in the following statements.
i ) A good source of energy would be one which would do a small amount of work
per unit volume of mass.
ii) Any source of energy we use to do work is consumed and can be used again.
4. The schematic diagram, in which different components of the circuit are represented by
the symbols conveniently used, is called a circuit diagram. What do you mean by the
term components?
5. The following graph was plotted between V and I values.What would be the values of
V / I ratios when the potential difference is 0.5 V and 1 V?
VOLT (V)
1.5
.5
.2
.4
I (A)
.6
6. We know that rays are harmful radiations emitted by natural radio active substances.
ii) Tabulate the following statements as applicable to each of the above radiations
7. Draw the schematic diagram of an electric circuit consisting of a battery of two cells of
1.5V each, three resistance of 5 ohm, 10 ohm and 15 ohm respectively and a plug key
all connected in series.
8. Fuse wire is made up of an alloy of ___________ which has high resistance and
_______.
269
CHAPTER 16
(They are electromagnetic radiation. They have high penetrating power. They are
electrons. They contain neutrons)
9. Observe the circuit given and find the resistance across AB.
1 ohm
1 ohm
B
1 ohm
1 ohm
6V
10. C
omplete the table choosing the right terms within the brackets.
(zinc, copper, carbon, lead, lead dioxide, aluminium.)
+ ve electrode
- ve electrode
Lechlanche cell
11. How many electrons flow through an electric bulb every second, if the current that
passes through the bulb is 1.6 A.
12. Vanis hair dryer has a resistance of 50 when it is first turned on.
i) How much current does the hair dryer draw from the 230 V line in Vanis house?
ii) What happens to the resistance of the hair dryer when it runs for a long time?
(Hint : As the temperature increases the resistance of the metallic conductor increases.)
13. In the given network, find the equivalent resistance between A and B.
10
10
10
10
14. Old fashioned serial lights were connected in a series across a 240V household
line.
i) If a string of these lights consists of 12 bulbs, what is the potential difference
across each bulb?
ii) If the bulbs were connected in parallel, what would be the potential difference
across each bulb?
PHYSICS
15. The figure is a part of a closed circuit. Find the currents i1, i2 and i3.
i1
1A
3A
i3
2A
i2
270
1.5A
A
10
15
10
V
6V
17. A wire of resistance 8 is bent into a circle. Find the resistance across the diameter.
18. A wire is bent into a circle. The effective resistance across the diameter is 8 . Find
the resistance of the wire.
19. Two bulbs of 40 W and 60 W are connected in series to an external potential difference.
Which bulb will glow brighter? Why?
20. Two bulbs of 70 W and 50 W are connected in parallel to an external potential difference.
Which bulb will glow brighter? Why?
21. Write about ocean thermal energy?
22. In a hydroelectric power plant, more electrical power can be generated if water falls
from a greater height. Give reasons.
23. What measures would you suggest to minimize environmental pollution caused by
burning of fossil fuel?
24. What are the limitations in harnessing wind energy?
25. What is biomass? What can be done to obtain bioenergy using biomass?
26. Which form of energy leads to the least amount of environmental pollution in the
process of harnessing and utilization? Justify your answer.
PART -C
1. Veenas car radio will run from a 12 V car battery that produces a current of 0.20 A even
when the car engine is turned off. The car battery will no longer operate when it has
lost 1.2 x 106 J of energy. If Veena gets out of the car, leaving the radio on by mistake,
how long will it take for the car battery to go completely dead, i.e. lose all energy?
(1 day =86400 second)
16 V
271
CHAPTER 16
2. Find the total current that passes through the circuit. Find the heat generated across
the each resistor.
12
3. Find the total current that passes through the circuit given in the diagram. Also find the
potential difference across 1 resistor.
1.5V
6
12
7. Explain the two different ways of harnessing energy from the ocean.
8. Five resistors of resistance R are connected such that they form a letter A. Find the
effective resistance across the free ends.
FURTHER REFERENCE
PHYSICS
Webliography: www.khanacademy.org
science.howstuffworks.com
http://arvindguptatoys.com/films.html
272
Chapter 17
MAGNETIC EFFECT OF
ELECTRIC CURRENT
AND LIGHT
Name : Oersted
Born
: 14th August 1777
Birth place
: Langeland Denmark
Died
: 9th March 1851
Best known for : The study of
electromagnetism
ACTIVITY 17.1
F
ix a sheet of white paper on a drawing
board using some adhesive material.
Place a bar magnet in the centre of it.
S
prinkle some iron fillings uniformly
around the bar magnet (Fig 17.1).
A
salt-sprinkler may be used for this
purpose.
Now tap the board gently.
What do you observe?
273
ACTIVITY 17.2
T
ake a small compass and a bar
magnet.
P
lace the magnet on a sheet of white
paper fixed on a drawing board, using
some adhesive material.
S
S
N
Fig 17.2
P
lace the compass near the north pole
of the magnet. How does it behave?
The south pole of the needle points
towards the north pole of the magnet.
The north pole of the compass is
directed away from the north pole of
the magnet.
M
ark the position of two ends of the
needle.
N
ow move the needle to a new position
such that its south pole occupies the
position previously occupied by its
north pole.
In this way, proceed step by step
till you reach the south pole of the
magnet as shown
J oin the points marked on the paper
by a smooth curve. This curve
represents a field line.
PHYSICS
R
epeat the above procedure and draw
as many lines as you can. You will get
a pattern as shown in Fig.17.3.These
lines represent the magnetic field
around the magnet. These are known
as magnetic field lines.
O
bserve the deflection of the compass
needle as you move it along the field
line. The deflection increases as the
needle is moved towards the pole.
Fig 17.3
17.2. M
AGNETIC FIELD DUE
TO CURRENT CARRYING
CONDUCTOR
In the activity 17.3, the electric current
through a metallic conductor produces a
magnetic field around it. If the current flows
in one direction (from X to Y), the north
274
ACTIVITY 17.3
T
ake a straight thick copper wire
and place it between the points
X and Y in an electric circuit, as
shown in Fig.17.4. The wire XY is
kept perpendicular to the plane of
the paper.
H
orizontally place a small compass
near this copper wire. See the
position of its needle.
T
ake a battery (12 V), a variable
resistance (rheostat), an ammeter
(0-5A), a plug key, and a long straight
thick copper wire.
P
ass the current through the circuit
by inserting the key into the plug.
O
bserve the change in the position
of the compass needle and the
direction of deflection.
Interchange the battery connection
in the circuit so that the direction
of the current in the copper wire
changes.
C
onnect the copper wire vertically
between the points X and Y, as
shown in Fig 17.5(a), in series with
the battery, a plug key, ammeter and
a rheostat.
O
bserve the change in the direction
of deflection of the needle.
Variable resistence
Fig 17.4
Fig.17.5(a)
S
prinkle some iron filings uniformly on
the cardboard. (You may use a salt
sprinkler for this purpose).
K
eep the rheostat at a fixed position,
close the key and note the current
through the ammeter.
275
CHAPTER 17
G
ently tap the cardboard a few times.
Observe the pattern of the iron filings.
Y
ou will find that the iron filings align
themselves showing a pattern of
concentric circles around the copper
wire, Fig 17.5(b).
W
hat do these concentric circles
represent? They represent the
magnetic field lines.
H
ow can the direction of the magnetic
field be found? Place a compass at a
point (say P) over a circle.
O
bserve the direction of the needle.
The direction of the north pole of
the compass needle would give the
direction of the field lines produced
by the electric current through the
straight wire at point P. Show the
direction by an arrow.
D
oes the direction of the magnetic
field lines get reversed if the direction
of current through the straight copper
wire is reversed? Check it.
PHYSICS
Fig.17.5(b)
276
Fig.17.6
T
ake a small aluminium rod AB of
about 5 cm. Using two connecting
wires suspend it horizontally from a
stand as shown in Fig. 17.8.
ACTIVITY 17.5
T
ake a rectangular cardboard having
two holes. Insert a circular coil having
large number of turns through them,
normal to the plane of the cardboard.
C
onnect the ends of the coil in series
with a battery, a key and rheostat, as
shown in Fig.17.7.
S
prinkle iron filings uniformly on the
cardboard.
C
onnect the aluminium rod in series
with a battery, a key and a rheostat.
N
ow pass a current through the
aluminium rod from end B to A.
W
hat do you observe? It is observed
that the rod is displaced towards the
left.
R
everse the direction of current
flowing through the rod and observe
the direction of its displacement. It is
now towards the right.
Why does the rod get displaced?
Fig.17.7
277
CHAPTER 17
Current
Thumb - Motion
Force
Current
Fig. 17.8
PHYSICS
Fig. 17.9
278
17.5. ELECTROMAGNETIC
INDUCTION
Faraday in 1831 discovered that
an electro motive force is produced in a
circuit whenever the magnetic flux is linked
with a coil changes. He showed that emf is
generated in a conductor whenever there
is a relative motion between the conductor
and a magnetic field.
The emf produced in this way is called
an induced emf and the phenomenon is
known as electromagnetic induction. The
induced emf will cause a current to flow
through the conductor. Such a current is
known as induced current. Faraday made
an important breakthrough by discovering
how a magnet can be used to generate
electric currents.
279
CHAPTER 17
Fig. 17.10
ACTIVITY 17.7
T
ake a coil of wire AB having a large
number of turns.
C
onnect the ends of the coil to a
galvanometer as shown in Fig.17.11
T
ake a strong bar magnet and move
its north pole towards the end B of the
coil.
D
o you find any change in the
galvanometer reading?
T
here is a momentary deflection
in the needle of the galvanometer,
say to the right. This indicates the
presence of a current in the coil AB.
The deflection becomes zero, the
moment the motion of the magnet
stops.
N
ow withdraw the north pole of the
magnet away from the coil. Now the
galvanometer is deflected towards
the left, showing that the current is
now set up in the direction opposite
to the first.
P
lace the magnet stationary at the
point near to the coil, keeping its north
pole towards the end B of the coil.
Fig.17.11
T
ake two different coils of copper wire
having large number of turns (say 50
and 100 turns respectively). Insert
them over a non conducting cylindrical
roll as shown in Fig.17.12.
W
e see that the galvanometer needle
deflects towards the right when the
coil is moved towards the north pole
of the magnet. Similarly the needle
moves towards left when the coil is
moved away.
PHYSICS
Coil -1
W
hen the coil is kept stationary with
respect to the magnet, the deflection
of the galvanometer drops to zero.
What do you conclude from this
activity?
Fig. 17.12
280
Coil -2
N
A
S1
B2
S2
A.C Generator
D.C Generator
Fig 17.13(a)
Fig 17.13(b)
281
CHAPTER 17
B1
R
17.7. LIGHT
We see a variety of objects in the world around us. However we are unable to see
anything in a dark room. On lighting up the room, things become visible. What makes
things visible? During the day the sunlight helps us to see objects. An object reflects light
that falls on it. This reflected light when received by our eyes, enables us to see things.
There are a number of common wonderful phenomena associated with light. In this
chapter, we shall study the phenomena of reflection and refraction of light using the
straight-line propagation of light.
PHYSICS
Reflection of Light
A highly polished surface, such as a mirror, reflects most of the light falling on it. You are
already familiar with the laws of reflection of light. Let us recall these laws.
(i) The angle of incidence is equal to the angle of reflection(i = r)
(ii) The incident ray, the normal to the mirror at the point of incidence and the reflected ray,
all lie in the same plane.
282
Hold the mirror and the paper in the
same position for a few minutes. What
do you observe? Why?
Fig 17.14
283
CHAPTER 17
At
Infinity
(a)
At Infinity
(b)
Fig. 17.15
PHYSICS
284
Fig. 17.17(a)
Fig. 17.17(b)
285
CHAPTER 17
their directions after reflection from the mirror. You may take any two of the rays mentioned
in the previous section for locating the image. The intersections of the two reflected rays
give the position of image of the point object. This is illustrated in the Fig.17.19.
Uses of Concave Mirror
Concave mirrors are commonly used in torches, search-lights and vehicles head
lights to get powerful parallel beams of light. They are used as shaving mirrors to see a
magnified image of the face. The dentists use concave mirrors to see large images of the
teeth of patients. Large concave mirrors are used to focus sun light to produce heat in
solar furnaces.
At Infinity
(a)
(b)
PHYSICS
(c)
(d)
(e)
(f)
Fig 17.19
286
Position of the
image
Nature of the
image
At infinity
At focus F
Highly diminished,
point-sized
Beyond C
Between F and C
Diminished
At C
At C
Same size
Between C & F
Beyond C
Enlarged
At focus F
At infinity
Highly enlarged
Between
P and F
Enlarged
Table 17.1
Image Formation by a Convex Mirror
We consider two positions of the object for studying the image formed by a convex
mirror. First when the object is at infinity and the second position is when the object is at
a finite distance from the mirror. The ray diagrams for the formation of image by a convex
mirror for these two positions of the object are shown in Fig 17.20(a) and (b), respectively.
M
M
A
A
P
A1
At Infinity
(a)
B1 F
(b)
Fig. 17.20
Position of the
object
Position of the
image
Relative size of
the image
Nature of the
image
At infinity
At focus F behind
the Mirror
Highly diminished,
point-sized
Between infinity
and Pole P of the
Mirror
Between P and F
behind the Mirror
Diminished
Table 17.2
287
CHAPTER 17
observations
O
bserve the image of a distant tree in
a concave mirror.
E
xplain
reason.
with
A1
PHYSICS
Distance towards
Mirror
N
Fig. 17.21
288
289
CHAPTER 17
Solution:
P
lace a coin at the bottom of a bucket
filled with water.
W
ith your eye to one side on the
surface of the water, try to pick up the
coin in one go. Did you succeed in
picking up the coin?
R
epeat the activity. Why did you not
succeed in doing it in one go?
A
sk your friends to do this. Compare
your experience with theirs.
The apparent position of the coin as seen
through water differs from its actual position.
Medium - 1
(Air)
PHYSICS
N'
Medium - 2
(Glass)
Fig. 17.22
290
sin r
291
ACTIVITY 17.13
C
AUTION: Do not look at the sun
directly or through a lens while doing
this activity or otherwise. You may
damage your eyes if you do so.
H
old a convex lens in your hand.
Direct it towards the sun.
F
ocus the light from the sun on a
sheet of paper. Obtain a sharp bright
image of the sun.
H
old the paper and the lens in the
same position for a while. Keep
observing the paper. What happens?
Why?
CHAPTER 17
Fig.17.23(a)
PHYSICS
Fig.17.23(b)
292
0
F1
F2
F2
F1
0
F1
Fig. 17.25(b)
Fig. 17.25(a)
0
F1
0
F1
F2
F2
F2
F1
F2
F1
F2
F2
(iii) A ray of light passing through the optical centre of a lens will emerge without any
deviation. This is illustrated in Fig 17.26(a) and (b). The ray diagrams for the image
formation in a convex lens for a few positions of the object are shown in Fig. 17.27.
(a)
(b)
(c)
(d)
(e)
Fig. 17.27
293
(f)
CHAPTER 17
C1
Position of the
image
Relative size of
the image
Nature of the
image
At infinity
At focus F2
Highly diminished,
point-sized
Beyond 2F1
Diminished
At 2F1
At 2F2
Same size
Beyond 2F2
Enlarged
At focus F1
At infinity
Infinitely large or
highly enlarged
Between focus F1
and optical centre O
Enlarged
Table 17.3
The ray diagrams for the image formation in a concave lens for various positions of the
object are shown in Fig. 17.28.
(a)
Fig. 17.28
(b)
PHYSICS
Position of the
object
Position of the
image
Nature of
the image
At infinity
At focus F1
Highly diminished,
point-sized
Virtual and
erect
Between focus
F1 and optical
centre O
Diminished
Virtual and
erect
Table 17.4
294
Magnification
1
1 1
= -
f v
u
Note:
Example: 17.3
An object is placed at a distance of 30
cm from a concave lens of focal length 15
cm. An erect and virtual image is formed at
a distance of 10 cm from the lens. Calculate
the magnification.
Solution:
Object distance, u = -30 cm
Image distance, v = -10 cm
u=?
Magnification, m = v/u
1
1
1
- = Or,
f
v u
-10
1
m = = = + 0.33
-30
3
1
1
1
= -
u
v
f
1
1
1
= -
u
-10
-15
1
-3 + 2
-1
= =
u
30
30
u = - 30 cm
295
CHAPTER 17
ACTIVITY 17.14
F
ix a sheet of white paper on a drawing
board using drawing pins.
P
lace a glass prism on it in such a
way that it rests on its triangular base.
Trace the outline of the prism using a
pencil.
Solution:
D
raw a straight line PE inclined to one
of the refracting surfaces, say AB, of
the prism.
1
P=
f
1
P=
-2
= - 0.5 dioptre
17.7.9.
Refraction of Light through a
Prism
Consider a triangular glass prism. It has
two triangular bases and three rectangular
lateral surfaces. These surfaces are inclined
to each other. The angle between its lateral
faces is called the angle of the prism(A). Let
us now do an activity to study the refraction
of light through a triangular glass prism.
F
ix two more pins, at points R and S,
such that the pins at R and S lie on the
same straight line.
Remove the pins and the glass prism.
T
he line PE meets the boundary of
the prism at point E (see Fig 17.29).
Similarly, join and produce the points
R and S. Let these lines meet the
boundary of the prism at E and F,
respectively. Join E and F.
D
raw a perpendicular to the refracting
surfaces AB and AC of the prism at
points E and F, respectively.
PHYSICS
Fig.17.29
PE - Incident ray
FS - Emergent ray
EF - Refracted ray
A - Angle of the Prism
M
ark the angle of incidence (i), the
angle of refraction (r) and the angle of
emergence (e) as shown in Fig 17.29.
i - Angle of incident
e - Angle of emergence
r - Angle of refraction
d - Angle of deviation
296
ACTIVITY 17.15
T
ake a thick sheet of cardboard and
make a small hole in its middle.
A
llow sunlight to fall on the narrow
slit. This gives a narrow beam of
white light.
N
ow, take a glass prism and allow
the light from the slit to fall on one of
its faces.
T
urn the prism slowly until the light
that comes out of it appear on a near
by screen.
W
hat do you observe? You will find a
beautiful band of colours.
White light
beam
Glass Prism
Fig. 17.30
R
O
Y
G
B
I
V
297
CHAPTER 17
Iris
Cornea
PHYSICS
Pupil
Vitreous
humour
Retina
Aqueous
humour
Crystalline lens
Optic nerve
Fig 17.31
298
Fig. 17.32
Fig. 17.33
299
CHAPTER 17
PHYSICS
Fig.17.34
300
7. An overhead wire carries current from east to west. Find the direction of the magnetic
field 5cm below the wire.
8. In the arrangement shown in the figure, there are two coils wound on a
non-conducting cylindrical rod. Initially the key is not inserted. Then the key is
inserted and later removed. Then, which of the following statement is correct?
a. The deflection in the galvanometer remains zero throughout.
b. There is a momentary deflection in the galvanometer but it dies out shortly.
10. A
pencil partly immersed in water in a glass tumbler appears to be bent at the
interface of air and water. Name the phenomenon of light responsible for it.
11. Sitting in her parlour one night, Chitra sees the reflection of her cat in the living
room window. If the image of her cat makes an angle of 400 with the normal,
at what angle does Chitra see the reflected image of the cat?
12. Why do the lines of the magnetic field not cross each other?
301
CHAPTER 17
9. Which part of the human eye helps in changing the focal length of the eye lens?
13. What is the magnetic field midway between two parallel conductors carrying same
amount of current in the same direction and in the opposite direction?
14. How can an AC generator be converted into a DC generator?
15. Compute the position of the object placed in front of a concave mirror of focal
length f so that the image formed is of the same size of the object.
PART - B
1. Fill in the blanks
i) For a motor : a permanent magnet, then commercial motor : _______
ii) Outside the bar magnet, the magnetic field lines emerge from the south pole and
merge at the north pole.
3. The ray diagram shown below is introduced to show how a concave mirror forms the
image of an object.
4. In traffic signals _________ colour light is used to stop vehicles because it has ______
wave length. (Hint: scattering of light is inversely proportional to the fourth power of its
wavelength)
5. F
ill the table with the appropriate words given in bracket.
_________
the tooths
enlarged image
_________
PHYSICS
(Convex mirror, Plano convex, Concave mirror, Plane mirror, Convex lens, Concave
lens)
6. Write down the names of the specified parts of the human eye.
ii) The screen where the image is formed by the eye lens.
302
8. i) Which of the compass needle orientations in the following diagram correctly describes
the magnets field at that point?
b
c
N
30
45
Medium 2
13. A real image, 1/5th the size of the object, is formed at a distance of 18 cm from a
mirror. What is the nature of the mirror? Calculate its focal length.
15. Explain the use of concave mirror as solar concentrators with the help of a ray
diagram.
16. Light enters from air to kerosene having refractive index of 1.47. What is the speed
of light in kerosene, if the speed of light in air is 3x108 m/s?
303
CHAPTER 17
14. A person cannot clearly see objects farther than 12 m from the eye. Name the
defect in vision he is suffering from and the lens that should be used to correct this
defect.
17. Murugan trims his beard while looking into a concave mirror whose focal length is
18 cm. He looks into it from a distance of 12 cm.
i) How far is Murugans image from the mirror?
ii) Does it matter whether or not Murugans face is closer or farther than the focal
length? Explain.
18. Light travels at 1.90 x 108 m/s in a crystal, what is the crystals index of refraction?
19. Ranjini makes arrangements for a candle-light dinner and tops it with a dessert
of gelatin filled blue berries. If a blueberry that appears at an angle of 450 to the
normal in air is really located at 300 to the normal in gelatin, what is the index of
refraction of the gelatin?
20. If the far point of a myopic person is 75 cm, what should be the focal length of the
lens used to rectify this defect?
21. Reena and Vani find a discarded plastic lens lying on the beach. The girls discuss
what they learnt in Physics and argue whether the lens is a converging or diverging
one. When they look through the lens, they notice that the objects are inverted.
i) If an object 25 cm in front of the lens forms an image 20 cm behind the lens,
what is the focal length of the lens?
ii) Is it a converging or diverging lens?
22. Light which is incident on a flat surface makes an angle of 150 with the surface.
i) What is the angle of incidence?
ii) What is the angle of reflection?
iii) Find the angle of deviation.
150
23. How can you identify the three types of mirrors without touching them?
Give reasons.
24. What will happen when the frequency of rotation in an AC dynamo is doubled?
PART - C
PHYSICS
1. a. D
raw the given diagram and label the following in the diagram.
i) Incident ray
ii) Refracted ray
iii) Emergent ray
iv) Angle of refraction
v) Angle of deviation
vi) Angle of emergence
b. The retractive index of diamond is 2.42. What is the meaning of this statement in
relation to the speed of light?
304
S
D
4. An object of 5cm tall is placed at a distance of 10cm from a concave mirror of radius
of curvature 30cm
i) F
ind the nature, position and size of the image
ii) D
raw the ray diagram to represent the above case.
5. The optical prescription of a pair of spectacle is
Right eye : - 3.5 D
Left eye : - 4.00 D
i) Name the defect of the eye
ii) Are these lenses thinner at the middle or at the edges?
iii) Which lens has a greater focal length?
Discuss in group
1. To an astronaut sky appears dark instead of blue
2. Two wires carrying current in the same direction attract each other. Will the two
beams of electrons travelling in the same direction get attracted? Reason out.
3. If a child crawls towards a mirror at the rate of 0.40 m/s, at what speed will its
image move with respect to the child?
FURTHER REFERENCE
4. P
rinciples of Physics(Extended) - Halliday, Resnick & Walker,
Wiley publication, New Delhi.
Webliography: www.physics about.com, www.khanacademy.org
science.howstuffworks.com http://arvindguptatoys.com/films.html
305
CHAPTER 17
Books: 1. Fundamentals of optics by D.R. Khanna and H.R. Gulati R.Chand & Co
ANSWERS
CHEMISTRY
Chapter 9. Solutions
PART - A
3. 16 g; PART - B 5. 28.57%
2. 2; 3. 22.4 litres;
5. 18 g;
6. 0.5 mole
PART - B
3. i) 2 moles; ii) 0.5 mole; iii) 0.25 mole, 4. i) 18 g; ii) 44 g; iii) 40 g; iv) 46 g; v) 98 g;
5. 16, 256, 2;
6. 6.023 x 10 21molecules
7. i) 40 g, 16 g, 56 g; ii) 40 g, 12 g, 48 g, 100 g
PART - C
NH4Cl
6. i) 0.142 mole; ii) 1 mole; iii) 1 mole; iv) 0.2 mole; v) 1 mole
PART - B
4. 6
7. i) A is CaCO3 ; B is CO2 ; ii) slaked lime; iii) C is CaCl2 ; D is H2O, iv) basic
18. i) 8; ii) 6; iii) The given solution is basic because the PH is greater than 7
PHYSICS
Chapter 15. Laws of Motion and Gravitation
SCIENCE
PART - B
5. F = -1125 N;
6. 19.5 N;
12. 9.8 N kg -1 ;
6. - 6 ms-1 ;
20. 0.4 m
5. 1: 36
306
9. 1 W;
11. 10 19
13. 5 W
16. 0.4 A
17. 2 W; 18. 32 W
5. 4 W,
8. 8 R
3
PART - C
20. - 75 cm
21. i) 11.11 cm, ii) converging lens. 22. i = 750 ; r = 750 ; d = 300
3. i) (a) Nature of the image : real, enlarged and inverted
Position of the image v = 30 cm
Magnification of the image = - 2
(b) Nature of the image : virtual, enlarged and erect.
Position of the image v = - 40 cm (same side of the object)
Magnification of the image = + 5
ANSWERS
307
SCIENCE
SYLLABUS
1.
Applied Biology
2.
Health and
Hygiene
Immune System:- Health and its significance-Diseases and causesDiseases caused by microbes and prevention-Modes of transmissionImmunization-Treatment and prevention-Biotechnology in MedicineHIV and Prevention
3.
My Body
Structure & Function of the Human Body Organ System:Nervous system-Endocrine system-Cell division-Stages of Meiosis.
4.
World of Plants
5.
World of Animals
A Representative Study of
Mammals- Morphology-HabitatsAdaptations-Basic physiological functions.-Circulatory system in
man-Excretory system in man.-Relationship of structure to functionsAnimal behaviour - Behaviour (social, reproductive, parental care)
-Some case studies from researchers(animals behavior)
6.
Life Process
7.
Environmental
Science - Ecology
8.
Environmental
Science
Resource Use and
Management
9.
Matter
Atomic Structure
Atoms and Molecules:- Modern atomic theory- Avogadro HypothesisAtomicity-Relation between vapour density and molecular mass of a
gas- Difference between-atom and Molecules-Relative atomic massRelative molecular mass-Mole concepts- Mole- definition-Problems
based on mole concept
10.
308
Exploring
Chemical Changes
and Formulation
Exploring
Chemical Families
13.
14.
Matter and
Measurement
12.
15.
Forces and
Movement
Exploring Energy
17.
Exploring
Phenomena
18.
Technology
16.
309
SYLLABUS
11.
Categories
Mark
PERCENTAGE
Knowledge
17
15
Understanding
56
45
Application
35
30
Skill
11
119
10
100
Total
Note: (1) Total Marks is 119 inclusive of choice. (2) While preparing the question paper, there may be
variations in weightage to the extent from 2 % to 5 %.
1
2
3
Marks
for Each
Question
Types of Questions
Section A
Objective Type (OT)
Section B
Short Answer (SA)
Section C
Long Answer (LA)*
Total
No. of
Questions
No. of Questions
to be answered
Total
Marks
15
15
15 x 1 = 15
32*
20
20 x 2 = 40
4 x 5 = 20
55
39
75
Total
* Each Question may be split into 2 or 3 sub-divisions carrying 1, 2 or 3 marks. But the questions shall
be from each area (Botany, Zoology, Chemistry, Physics). Choices will be internal (Either - or)
SCIENCE
Sl.No.
1
2
3
4
5
6
7
8
9
10
To Match
To spot the error / mistake in the given statements
Reason and assertion
To Raise questions
To label the parts in the given diagram
To copy a diagram & to identify /mark the parts
To calculate the required value(Problem solving)
To fill in the blanks (from the given pair of answers)
To interpret what happens in the given situations
To find the odd one out
Total Number of Questions given
Total Number of Questions to be answered
310
To be
asked
3
3
3
5
3
3
3
3
3
3
32
20
Sl.No
Easy
20
Average
60
Difficult
20
Total
Marks
SA
LA
1(1)
3(2)
2. Immune System
1(1)
1(2)
1(5)
1(1)
1(2)
1(5)
1(1)
1(2)
1(5)
1(1)
3(2)
1(1)
3(2)
1(2)
1(5)
1(1)
3(2)
9. Solutions
1(1)
2(2)
1(2)
1(5)
1(1)
2(2)
1(1)
2(2)
1(1)
1(2)
1(5)
14. Measurements
1(1)
1(1)
2(2)
1(5)
10
1(1)
3(2)
1(1)
3(2)
1(5)
15(15)
32(64)
8(40)
55
119
15(15)
20(40)
4(20)
39
75
OT
Chemistry
7. Conservation of Environment
Physics
27
14
14
8
7
7
5
7
12
SYLLABUS
Units
312
Bot
Che
Che
Che
Waste Water
Management
Solutions
Chemical Reaction
Periodic Classification
of Elements
10
11
12
13
Phy
Phy
Phy
15
16
17
Total
Phy
Measurements
14
Che
Che
Bot
Conservation of
Environment
Zoo
A Representative Study
of Mammals
Life Processes
Bot
Zoo
Reproduction in Plants
Human Body
Zoo
Zoo
Subject
Related
Immune System
Content Unit
No.
Unit
SCIENCE
5(5)
1(1)
1(1)
1(1)
1(1)
1(1)
OT
5(10)
1(2)
1(2)
1(2)
1(2)
1(2)
SA
LA
1(5)
1(5)
Knowledge
9(9)
1(1)
1(1)
1(1)
1(1)
1(1)
1(1)
1(1)
1(1)
1(1)
OT
13(26)
1(2)
1(2)
1(2)
1(2)
1(2)
1(2)
2(2)
1(2)
1(2)
3(2)
SA
LA
4(20)
1(5)
1(5)
1(5)
1(5)
Understanding
BLUE PRINT
1(1)
1(1)
OT
10(20)
1(2)
1(2)
1(2)
1(2)
1(2)
1(2)
1(2)
1(2)
1(2)
1(2)
SA
Application
3(15)
1(5)
1(5)
1(5)
LA
OT
4(8)
1(2)
1(2)
1(2)
1(2)
SA
Skill
LA
55
Total No.
of Questions
119
12
10
Marks
Total
SCIENCE PRACTICALS
S.No.
PART - 1
CONTENTS
BIOLOGY
BIO-BOTANY
1
Dissect
and display the floral parts like Calyx, Corolla, Androecium and
Gynoecium of a flower
5
Identify the given slide, draw a neatly labelled diagram and write a
note on it.
alculate the Body Mass Index (BMI) of a person, by using the BMI
C
formula and comparing the value with BMI chart.
CHEMISTRY
7
ou are provided with a solid sample. Prepare a solution and identify the
Y
type of solution based on filtration
10
Screw Gauge
11
12
Resistors in Series
PRACTICALS
PHYSICS
313
BIO-BOTANY
Exercise No : 1 Date :
Dissect and display the floral parts like Calyx, Corolla, Androecium and Gynoecium of
a flower.
Floral parts
1. Calyx
Accessory Organs
2. Corolla
3. Androecium Male parts of the flower
4. Gynoecium Female parts of the flower
Calyx
Corolla
Sepal ________
________ petal
Gynoecium
Androecium
Stigma
Anther
SCIENCE
Style
Ovary
Filament
314
Exercise No : 2 Date :
Identify the given slide with the help of microscope.
(a) T.S of Anther
Each anther lobe is covered by a 4 layered wall.
The inner most layer of the wall is called tapetum.
Inner side of the anther wall pollen sac (microspore) with pollen mother cell
(micropore mother cell ) is present.
The pollen mother cell divides meiotically to produce pollen grains.
Epidermis
Endothecium
Tapetum
Pollen sac
Pollen grain
Nucellus
Embryo sac
Egg
Integuments
Micropyle
Funiculus
L.S of Ovule
315
PRACTICALS
Chalaza
Exercise No : 3 Date :
Fermentation Experiment (Anaerobic Respiration).
Aim :
To prove the fermentation process.
Materials and apparatus required:
Sugar solution, Bakers yeast, conical flask (250ml), beaker and lime water.
Procedure:
Take sugar solution with a small quantity of bakers yeast in a (2/3) conical flask.
Close the mouth of the conical flask with a one holed rubber cork and insert a
delivery tube in the cork.
Immerse the other end of the delivery tube in a beaker containing lime water.
Keep the apparatus in sunlight for 2 hours.
Observation:
After 2 hours, it is observed that the lime water in the beaker turns milky.
Remove the stopper of the flask, An alcoholic smell is observed.
Inference:
Due to fermentation of sugar solution, CO2 is released and ethanol is formed.
The CO2 turns the lime water milky and the smell is due to the formation of ethanol.
Hence the process of fermentation is proved.
Delivery tube
Cork
SCIENCE
Conical flask
Beaker
Lime water
316
BIO-ZOOLOGY
Exercise No : 4 Date :
Test for Starch ( Iodine test).
Aim :
To find out the presence of starch in the given food samples A, B and C by Iodine test.
Materials and apparatus required:
ood sample A, B and C, Iodine solution, test tubes, test tube holder and test tube
F
stand.
Procedure:
Take 1ml of food samples A , B and C in three different test tubes.
Add one drop of Iodine solution each of the test tubes and mix well.
Note the changes that occur in the colour and tabulate the results.
Observation:
Sample A :
Sample B :
Sample C :
Table:
Sample
Observation
Inference
A
B
Result:
Appearance of dark blue colour in the Sample _______ indicates the presence of
starch.
317
PRACTICALS
Exercise No : 5 Date :
Identify the given slide, draw a neatly labelled diagram and write a note on it.
(a) Red Blood Corpuscles
Identification:
The given slide is identified as Red Blood Corpuscles - (Erythrocytes)
Cytoplasm
Plasma
Membrane
RBC
Notes:
RBCs are circular, biconcave and disc shaped.
The young RBCs have a nuclei but the mature RBCs do not have a nuclei.
RBCs are red due to the presence of a respiratory pigment called haemoglobin.
RBCs are concerned with the carriage of oxygen.
Decrease in RBCs causes Anaemia, increase in number causesPolycythemia.
(b) White Blood Corpuscles (Leucocyte)
Identification:
The given slide is identified as White Blood Corpuscles (Leucocyte)
SCIENCE
Cytoplasm
Cytoplasm
Nucleus
Neutrophil
Nucleus
Eosinophil
318
Basophil
Cytoplasm
Nucleus
Notes:
Lymphocyte
Monocyte
(c) Plasmodium
Identification:
The given slide is identified as Plasmodium
Conoid
Apical polar ring
Notes:
Dense granules
Inner membrane
Mitochondrion
Nucleus
Endoplasmic reticulum
Plasma membrane
Plasmodium is a protozoan organism.
Posterior pole
319
PRACTICALS
Exercise No : 6
Date :
To calculate the Body Mass Index (BMI) of a person, by using the BMI formula and
comparing the value with BMI chart.
Aim:
To calculate the BMI of any one of your classmates by using BMI formula.
Materials required :
Weighing machine, measuring tape.
Procedure:
Find out the weight in kg of your classmate by using a weighing machine.
Find out the height in meter of the same person. Convert the height into meter2.
By using the formula
find out the BMI and record it.
Weight in Kg
BMI = ___________
Height in M2
Students
Name
Weight in
Kg
Height in
Meter
Height in
Meter2
BMI
1.
2.
SCIENCE
Inference:
1. BMI of my classmate Sl.No 1. ____________ is __________. Hence
he/she is ____________.
2. BMI of my classmate Sl.No 2. ____________ is __________. Hence
he/she is ____________.
320
CHEMISTRY
Exercise No: 7 Date :
You are provided with a solid sample. Prepare a solution and identify the type of
solution based on filtration.
Aim:
To prepare a solution from the solid sample and identify the type of solution based
on filtration.
Materials required :
Beaker, water, glass rod, filter papers, test tube, test tube stand, funnel and given
solid sample.
Theory:
A true solution is a homogenous and transparent. It completely passes through
filter paper.
A suspension is a heterogeneous mixture. Here solute particles settle down on
standing and can be filtered by filter paper.
Procedure:
Experiment
Observation
Inference
a) True solution.
b) Suspension.
Result:
PRACTICALS
321
Exercise No : 8
Date :
Prepare a solution from the given salt, identify whether it is an unsaturated solution or
saturated solution.
Aim:
To prepare a solution from the given salt and identify whether it is an unsaturated
solution or saturated solution.
Theory:
Unsaturated solution is a solution in which more of the solute can be dissloved at
a given temperature.
A solution in which no more solute can be dissolved in a definite amount of solvent
at a given temperature is called a saturated solution.
Materials required :
Beaker, 50 ml of water, a glass rod and given salt.
Procedure:
Experiment
Observation
Inference
a) The solution is
unsaturated.
b) The solution is
saturated solution.
Result:
SCIENCE
322
Exercise No : 9 Date :
To identify the carboxylic or alcoholic functional group present in the given organic
compound. By performing the following test 1) Blue litmus paper 2) Sodium carbonate
3) acidified potassium dichromate.
Aim : T
o identify the carboxylic or alcoholic functional group present in the given organic
compound.
Theory : Alcohols are neutral and it will not affect the blue litmus paper and sodium
carbonate. Alcohols are oxidized by acidified potassium dichromate. Carboxylic acids are
the most acidic amongst the organic compound. Carboxylic acid affects the blue litmus
paper and liberates carbon dioxide with sodium carbonate by forming salt.
2CH3COOH + Na2CO3
C2H5OH + O2
Materials required:
Test tubes, blue litmus paper, glass rod, sodium carbonate, salt, phenolphthalein
solution, acidified potassium dichromate solution and the given organic compound.
Procedure:
1.
Experiment
Observation
Inference
a) No brisk
effervescence.
b) Brisk
effervescences.
323
PRACTICALS
S.No.
PHYSICS
Exercise No : 10 Date :
Screw Gauge
Aim:
To find out the thickness of the given one rupee coin.
Materials required :
screw gauge, one rupee coin.
Formula :
Pitch
Least count = ___________
No. Of HSD
S1
U-Shaped Frame
pitch scale
Head Scale
SCIENCE
Index line
positive error
no error
negative error
Procedure:
The least count of the screw gauge is found by using the formula.
Zero error of the screw gauge is found in the following way.
324
The plane surface of the screw S2 and the opposite plane stud on the frame S1are
brought into contact. If zero of head scale coincides with the pitch scale axis, there
is no zero error. If the zero of the head scale lies below the pitch scale axis, the
zero error is positive. If the nth division of the head scale coincides with the pitch
scale axis
ZE = + (n LC )
Then the zero correction is ZC = - (n LC )
If the zero of the head scale lies above the pitch scale axis, the zero error is negate.
If the nth division of the head scale coincides with the pitch scale axis,
ZE = - (100 n) LC
Then the zero correction is ZC = + (100 n) LC
Place the given coin between two studs. Rotate the head until the coin is held
firmly but not tightly. Note the pitch scale reading (PSR) and the head scale division
which coincides with the pitch scale axis (HSC). The thickness of the wire is given
by PSR + (H.S.C LC) + ZC.
Repeat the experiment for different positions of the coin. Tabulate the readings.
The average of the readings gives the thickness of the coin.
Table:
Pitch =
Trial
No.
P.S.R
(mm)
L.C =
H.S.C
(division)
Z.E =
H.S.C x L.C
(mm)
Z.C =
1.
2.
3.
5.
Mean
Result:
The thickness of the given coin = ______ mm
325
PRACTICALS
4.
()
XY
Resistor
of value R
Procedure:
SCIENCE
Note the range and least count of the given ammeter and the voltmeter.
Set up the circuit by connecting different components with the help
of connecting wires. Keep the rating of the eliminator at the minimum
(say at 2 V)
Make sure that the positive and negative terminals of the ammeter and voltmeter
are correctly connected in the circuit as shown above.
326
Insert the key into the plug to let the current flow in the circuit. Note the readings of
the ammeter and voltmeter and record them. The voltmeter measures the potential
difference (V) across the two ends X and Y of the resistor, and the ammeter
measures the current I through it. Remove the key from the plug.
Now increase the rating of the Battery Eliminator rating to 4 V. Note and record the
voltmeter and ammeter readings.
Repeat the experiment by varying the rating of the battery eliminator to 6 V and 8V.
Observations and Calculations:
1.
= ______ to _____A
2.
3.
4.
=_______to _____V
Table:
Sl.
No.
Voltage applied
in the circuit
(in volt)
Current through
the Resistor, I
(in ampere)
Potential difference
across the ends of
the resistor, V (in
volt)
Resistance of the
resistor
R=V/I
(in ohm)
1.
2.
3.
4.
PRACTICALS
327
Graph:
Find the range of variation in the values of I and V. Choose appropriate scale for
the values of I and V along the x and y-axes respectively on the graph paper. Mark
the points on the graph paper for each value of current I and corresponding value
of potential difference V. Join all the points by a straight line such that most of the
points lie on it. Find the slope of this straight line graph by choosing two points P
and Q on it. The slope is the resistance of the resistor used in the circuit.
Extend the straight line of the graph backwards to check whether it passes through
the origin of the graph.
Slope
QM
= ___________
MP
v2-v1
= ___________
I2-I1
---
----
-------------------------
--------------------------
Result:
----------------
---
--V2 ------------------------------ Q
---P ---V1
M
-----------I1
I2
Current (A)
SCIENCE
=_________ohm.
The value of resistance R of resistor for all values of current through it remains the
same. The graph between V and I is a straight line and passes through the origin.
This verifies the Ohms law.
328
Exercise No : 12 Date :
Resistors in Series
Aim:
To determine the equivalent resistance of two resistors connected in series.
Materials required :
Two resistors of each 2 , an ammeter (range 0-5 A), a voltmeter
(range 0-5 V), a battery eliminator, a plug key and connecting wires.
Formula :
Effective Resistance of the Resistors connected in series Rs = R1 + R2
Circuit diagram :
()
A R1 B C R 2
R1R2
Resistor
Procedure:
Note the range and least count of the given ammeter and the voltmeter.
Insert the key in the plug to let the current flow in the circuit. Note the readings
of the ammeter and voltmeter and record them. The voltmeter measures the
potential difference (V) across the two ends A and D of the series combination of
two resistors. And the ammeter measures the current I through series combination.
329
PRACTICALS
The given resistors are connected in series by joining the ends labelled B and C as
shown in the circuit diagram. Set up the circuit by connecting different components
with the help of connecting wires.
Repeat the experiment with three different values of current flowing through
the circuit and record the readings of the ammeter and voltmeter in each case.
The current flowing through the circuit may either be decreased or increased by
changing the voltage rating of the battery eliminator.
Observations and Calculations:
1.
= ______ to _____A
2.
= _______A
3.
= _______to _____V
4.
5.
6.
= _______ V
Table:
Current
Potential
Voltage
through
difference
Sl. applied
the Series
across
No. in the
Combination, the series,
circuit
Is
Vs
(in volt)
(in ampere)
(in volt)
Equivalent
Resistance
of the
combination
Rs=Vs/Is
(in ohm)
Experimental
Average
value of
Rs
(in ohm)
Theoretical
Average
value of
Rs=R1+ R2
(in ohm)
1.
2.
3.
4.
R1
SCIENCE
Result:
The equivalent resistance of the series combination of the two given resistors is
found to be the same in the experimental and theoretical value.
330
BIO-BOTANY
PRACTICAL INSTRUCTIONS
1.To Dissect and display the parts of a flower (any one)
a) Hibiscus, Datura, Clitoria and Thespesia.
b) Separate out the Calyx, Corolla, Androecium and Gynoecium and display them
on a separate sheet
c) Draw a labelled sketch of the floral parts.
d) Marks:
Dissection 1
Display
=3
2. To identify the given slide and to draw a neatly labelled diagram with notes (any
one )
a) L.S of Anther
b) L.S of Ovule
Identification 1
Reasons
2x1 = 2
Identification :
Aim
Material required 1
Procedure 1
Observation 1
331
PRACTICALS
Inference
BIO-ZOOLOGY
4. To test the presence of starch by iodine test method.
Sample A & B one sample should contain starch solution and the other should be
a dummy sample.
Starch sample potato extract, starch powder, rice water (any one can be used )
Materials required 1
Procedure
Table
Result
5. To identify the given slide and to write notes with a neatly labelled diagram.
(any one)
a) Red blood corpuscles
b) White blood corpuscles
c) Plasmodium
Identification 1
Reason 2
Diagram + parts 2
6. To calculate the Body Mass Index using BMI formula.
Material required 1
Procedure
Table
Inference
SCIENCE
332
CHEMISTRY
Scoring method:
Aim
1 mark
Least count
1 mark
Procedure
1 mark
Tabulation
1+1 mark
Result +unit
1 mark
2. Ohms Law
Formula
1/2 mark
Circuit diagram
1/2 mark
Procedure
1 mark
Tabulation
1 mark
Graph
1 mark
Result + unit
1 mark
3. Resistance in Series
1/2 mark
Circuit diagram
1/2 mark
Procedure
1 mark
Tabulation
1+1 mark
Result + unit
333
1 mark
PRACTICALS
Formula
SCIENCE PRACTICALS
S.No.
PART - 2
CONTENTS
BIOLOGY
BIO-BOTANY
1 Identify the given seed and classify whether it is a dicot or a monocot
seed
2
BIO-ZOOLOGY
Identify the flagged endocrine gland and write its location, the hormones
secreted and any two of its functions
CHEMISTRY
7 You are provided with a sample solution. Perform the following tests and
identify whether the given sample is an acid or a base
8 You are provided with samples A&B. Identify if the samples are acids/
bases/neutral by using pH paper
9
IdIentify the basic radical presence in the given salt using sodium
hydroxide solution
SCIENCE
PHYSICS
10
11
Glass prism
12
334
BIO-BOTANY
Exercise No : 1 Date :
Identify the given seed and classify whether it is a dicot or a monocot seed.
Plumule
Hypocotyl
Radicle
Cotyledon
Endosperm
Hypocotyl
Radicle
Cotyledon
Seed coat
335
PRACTICALS
Exercise No : 2 Date :
Classify the given fruit and give reasons with diagram.
(a) Tomato
(i) Classification : Simple fleshy fruit Berry L.S. of Tomato
(ii) Reasons :
F
ruit is developed from the single flower, multicarpellary, syncarpous and
superior ovary.
The succulent pericarp is differentiated into outer epicarp and inner fleshy pulp.
T
he mesocarp and endocarp are fused to form the fleshy pulp where the seeds
are embedded.
The entire fruit is edible.
(iii) Diagram :
L.S. of Tomato
Epicarp
Mesocarp and
Endocarp
SCIENCE
Seed
336
Entire fruit
(b) Polyalthia
(i) Classification : Aggregate fruit (e.g.) Polyalthia
(ii) Reasons:
Polyalthia develops from a single flower with multicarpellary apocarpous ovary.
During fruit formation each free carpel develops into a fruitlet.
So, there are many fruitlets seen attached to a common stalk.
(iii) Diagram :
Entire fruit
Receptacle
Fruitlet
(iii) Diagram :
Peduncle
Seed
Edible perianth
337
PRACTICALS
Exercise No : 3 Date :
Test tube and funnel experiment
Aim :
To prove that Oxygen is evolved during Photosynthesis.
Materials required:
Test tube, funnel, beaker, pound water and Hydrilla plant.
Procedure:
Take a few twigs of Hydrilla plant in a beaker containing pond water.
Place an inverted funnel over the plant.
Invert a test tube filled with water over the stem of the funnel.
Keep the apparatus in the sunlight for few hours.
Observation:
After one hour, it is noted that water gets displaced down from the test tube.
Inference:
D
uring photosynthesis, Oxygen is evolved as a by product. Gas bubbles liberated
from the Hydrilla plant reach the top of the test tube and it displaces the water
downwards. Take the test tube and keep the burning stick near the mouth of the
test tube. Increased flame will be appeared. Hence, it is proved that Oxygen is
evolved during photosynthesis.
Diagram :
Test tube
SCIENCE
beaker
funnel
Hydrilla
338
BIO-ZOOLOGY
Exercise No : 4 Date :
Test for lipids (Saponification Test).
Aim :
To find the presence of Fat in the given food samples A and B by saponification test.
Materials required:
Test tubes, test tube holder and test tube stand, food samples A and B, 5% NaOH.
Procedure:
Take 1 ml of sample solution A and B separately in clean test tubes.
Add 2 ml of 5% NaOH in each test tube and shake well.
After noting the changes the reslts are tabulated.
Observation:
Sample A :
Sample B :
Table:
Sample
Observation
Inference
A
B
Result:
PRACTICALS
339
Exercise No : 5 Date :
Identification of given models.
(a) L.S. of Human heart
Identification: The given model is identified as a L.S.of Human Heart
Diagram :
Aorta
Superior venacava
Pulmonary artery
Left atrium
Right atrium
Tricuspid valve
Left ventricle
Right ventricle
Cardiac muscle
Inferior venacava
Notes:
The heart is a hollow fibro muscular organ, which is conical in shape.
The heart is covered by a protective double walled sac called pericardium.
The heart is made up of a special type of muscle called cardiac muscle.
It has four chambers namely two auricles and two ventricles.
SCIENCE
The heart is a pumping organ which pumps blood to all parts of the body.
340
Pons
Medulla
Cerebellum
Notes:
The human brain is placed inside the cranial cavity.
It is covered by three protective coverings called meninges.
T
he human brain is divided into three major parts namely forebrain, midbrain and
hind brain.
The human brain contains millions of neurons.
PRACTICALS
341
Renal Papilla
Fat in renal
sinus
Renal sinus
Renal Vein
Renal Pyramid in
renal medulla
Ureter
Capsule
Notes:
The kidney is the principal excretory organ of our body.
T
he kidney is bean shaped paired structure and located in the upper abdominal
region.
A thin transparent membrane called capsule covers the kidney.
T
he outer portion of the kidney is the renal cortex and the inner portion is the renal
medulla.
SCIENCE
342
Exercise No : 6 Date :
Identify the flagged endocrine gland and write its location, the hormones secreted and
any two of its functions. (No need to draw the diagram. Between two models anyone
may be considered in examination).
1. Endocrine glands (a) Thyroid gland
343
PRACTICALS
2. Any one endocrine gland should be flag labelled. For the purpose of flag labelling a
model or a chart or a neat drawn diagram showing all endocrine glands should be
used.
SCIENCE
Hormones secreted:
1. cells secrete glucagon and
2. cells secrete insulin and amylin.
344
Functions of Hormones:
1. Insulin converts glucose into glycogen and deposits it in liver and muscles.
2. Glucagon converts glycogen into glucose.
Insulin and glucagon together control the blood sugar level (80 120 mg/1dl) by their
antagonistic function.
3. Decrease in insulin level causes diabetes mellitus.
(c) Adrenal Gland
Identification:
The marked endocrine gland is Adrenal gland.
Location: Adrenal glands are located above each kidney in the abdominal region.
Hormones secreted:
Adrenal cortex Aldosterone and Cortisone.
Adrenal medulla Adrenaline and Nor-Adrenaline
Functions of Hormones:
Aldosterone regulates mineral metabolism.
PRACTICALS
345
Exercise No :7
CHEMISTRY
Date :
You are provided with the sample solution. Perform the following test, identify whether
the given sample is an acid or a base.
a) Phenolphthalein
c) Sodium carbonate
b) Methyl orange
d) Zinc granules
Aim:
To identify the presence of an acid or a base in a given sample.
Theory:
In acid medium, phenolphthalein is colourless whereas methyl orange is pink colour.
Similarly, in basic medium, phenolphthalein is pink in colour where as methyl orange
is yellow in colour. Acid gives brisk effervescence with sodium carbonate due to the
liberation of carbon dioxide whereas bases do not. Zinc reacts with dilute acid to
liberate hydrogen gas where bases will liberate hydrogen only on heating.
Materials required:
est tubes, test tube stand, glass rod, phenolphthalein, methyl orange, sodium
T
carbonate salt, zinc granules and the given sample.
SCIENCE
S.
No.
Experiment
Observation
(Colour change)
Inference
(Acid / base)
346
a) Presence of acid
b) Presence of base
a) Presence of acid
b) Presence of base
Exercise No : 8 Date :
You are provided with sample A&B.Find the nature of the samples as acids/bases/
neutral by using pH paper.
Aim:
To identify the nature of the given solution using pH paper.
Principle:
pH paper is the power of H+ ions or OH- ions present in a solution. The pH scale values
varies from 0 to 14. A pH less than 7 indicates acidic nature whereas pH greater than
7 indicates basic nature. pH equal to 7 indicates neutral. The pH paper is used for finding
the approximate pH value. It shows different colour at different pH.
Materials required:
Sample solutions A&B, pH paper, glass rod and watch glass.
Procedure:
Take a pH paper. Place it on a watch glass. By using glass rod take a drop of each
sample and place it on the pH paper. Observe the colour change that appeares and note
down the approximate pH value based on the reference scale given on pH paper.
Observation:
pH paper
Sample
Colour produced
Approximate pH
Inference
Nature of solution
B
Result:
The given sample A is _____________ in nature.
B is _____________ in nature.
347
PRACTICALS
Exercise No : 9 Date :
Identify the basic radical presence in the given salt using sodium hydroxide solution.
Aim :
To identify the basic radical present in the given salt by the action of sodium hydroxide
solution.
Theory:
Most of the metals generally form the precipitate of respective metal hydroxide with
sodium hydroxide solution.
Cu+2 + 2OH-
Fe+2 + 2OH-
Al+3 + 3OH-
Al(OH)3
White precipitate
Materials required:
Test tube, test tube stand, sodium hydroxide solution, distilled water and given salt.
Procedure:
Dissolve a few grams of the given salt in 10 ml of distilled water. This solution is called
salt solution. Take a small portion of that salt solution in a test tube and perform the test
given below.
S.No
SCIENCE
Experiment
Observation
(Colour change)
Inference
(Acid/base)
a) Bluish white
a) Presence of cupric ion
precipitate is formed
(Cu+2)
b) Dirty green
b) Presence of ferrous
precipitate is formed
ion (Fe+2)
c) White
precipitateis formed
Result:
The given salt contains _____________basic radical.
348
c) Presence of Aluminium
ion (Al+3)
PHYSICS
Exercise No : 10 Date :
Focal length of convex lens.
Aim:
Materials required :
Convex lens, lens stand, white screen, metre scale, and illuminated wire gauze.
Formula :
Focal length of the convex lens by u-v method
cm
Rays from a
distant tree
Principal axis
349
PRACTICALS
Diagram :
v
u-v method
u-v method
1. The convex lens is mounted on the stand and placed in front of the illuminated wire
gauze at a certain distance u from the wire gauze.
2. The screen is adjusted to get a clear image. Two values of u are chosen between
f and 2f of the lens and the other two values of u are chosen beyond 2f.
3. A screen is placed on the other side of lens and its distance from the lens is adjusted
to get a clear image. The value of u lesser than 2f will produce an enlarged image
and that greater than 2f will produce a diminished image.
4. The distance between the lens and the screen is taken as v and it is measured for
each experimental value of u focal length of the convex lens by u-v method
Table :
u-v Method
Trial
No.
Nature of
image
1.
u < 2f
magnified
2.
3.
Object distance
u cm
Image distance
v cm
u > 2f
diminished
4.
SCIENCE
Result:
The focal length of the given convex lens by:
i.
ii.
350
Focal length
uv
f = _______ cm
u+v
Exercise No : 11
Date :
Glass Prism
Aim:
To trace the path of a ray of light through a glass prism, to identify the rays and to
measure different angles.
Materials required :
A glass prism, drawing board, white paper, adhesive tape or drawing pins, pins, a
measuring scale, and a protractor.
Procedure :
1. F
ix a white sheet of paper on a drawing board. Draw a thin line XY in the middle
of the paper.
2. D
raw a thin line NEN normal (perpendicular) to the line XY at point of incidence E
(say). Also draw a line DE making an angle, preferably between 30 and 60.
I
4. Fix two pins P1 and P2 vertically, by gently pressing their heads with thumb on line
DE at a distance of about 6 cm from each other. View the images of pins P1 and
P2 from the opposite face AC of the prism.
5. Fix two more pins P3 and P4 vertically such that the feet of pins P3 and P4 appear
to be on the same straight line as the feet of the images of the pins P1 and P2 as
viewed through the face AC of the prism.
351
PRACTICALS
3. P
lace the prism with one of its refracting surfaces (say AB) along the line XY. Mark
the boundary ABC of the glass prism holding it firmly with your hand.
6. R
emove the pins and the prism. Mark the position of feet of pins P3 and P4 on the
sheet of paper. Draw a straight line to join the points that mark the position of pins
P3 and P4. Extend this line so that it meets the face AC of the prism at point F. The
line FG represents the path of the emergent ray.
7. E
xtend the direction of incident ray DE till it meets the face AFC. Also extend
(backwards) the emergent ray FG as shown in the Figure. These two extended
lines meet at point H.
8. Measure DEN as the angle of incidence( i ),
and
FHI as the angle of deviation( d). Record these angles in the observation
table.
Sl. No.
Angle of incidence ( i )
Angle of deviation ( d )
1.
2.
Result :
1. The path of light incident on one face of a glass prism is shown.
2. The different rays and angles are identified as below
Incident ray
_______
angle of incidence
Refracted ray
_______
Emergent ray
_______
angle of deviation
SCIENCE
352
_______
_______
Exercise No : 12 Date :
Mapping of magnetic field
Aim:
To map the magnetic field of a Bar Magnet when it is placed in a Magnetic Meridian
with its North-pole pointing towards North.
Apparatus required:
Drawing Board, board pin or sellotape(sticky tape), compass needle, sheets of
white paper and bar magnet.
Diagram :
N
E
W
S
Procedure:
2. A small plotting compass needle is placed near the edge of the paper and the
board is rotated until the edge of the paper is parallel to the magnetic needle. This
position should not be disturbed throughout the experiment.
3. T
he compass needle is placed at the centre of the paper, the ends of the needle
i.e. the new positions of the north and South Pole are marked when the needle
comes to rest. These points are joined and a straight line is obtained. This is the
magnetic meridian.
353
PRACTICALS
1. A white sheet of paper is fastened to the drawing board using board pins or sello
tape. (When doing this, all magnets and magnetic materials are moved far away
from the drawing board).
4. C
ardinal directions NEWS is drawn near the corner of the paper. The bar magnet is
placed on the line at the centre of the paper with its north pole facing the geographic
north. The outline of the bar magnet is drawn.
5. T
he plotting compass is placed near the North Pole; the ends of the needle are
marked. Move the compass to a new position such that its south end occupies the
position previously occupied by its north pole. In this way proceed step by step till
the South Pole of the magnet is reached.
6. The lines of the magnetic forces are drawn by joining the plotted points around the
magnet. In the same way several magnetic lines of force are drawn around the
magnet as shown in the figure.
7. T
he curved lines represent the magnetic field of the magnet. The direction of the
lines is shown by arrows heads.
Result:
The magnetic lines of force are mapped when the bar magnet is placed with its north
pole facing geographic north. The mapped sheet is attached.
BIO-BOTANY
1. To identify the given seed Whether it is a Dicot or a monocot seed.
1.Bean, Bengal gram, Paddy, Maize (any one)
2.The cotyledons of the seed should be separated and displayed.
3.Labeled diagram of the structure of seed should be drawn.
Classification
Diagram + parts
SCIENCE
Classification
Diagram + parts
Reasons
354
3. To demonstrate that oxygen is evolved during photosynthesis by test tube and
funnel experiment.
The physiological experiments must be demonstrated in the laboratory during
practical hours.
For the examination the experimental set up should be displayed.
Students should identify the experimental set up and write notes on it.
Identification
Aim
Material required
Procedure
Observation
Inference
BIO-ZOOLOGY
4. To test the presence of lipid by Soapanification test method - Sample A&B - One
Sample should contain lipid solution and the other should be a dummy solution.
Materials required 1
Procedure
Table
Result
a) Human Heart
b) Human brain
c) Human Kidney
Identification
Diagram + Parts
Notes
355
PRACTICALS
2. Any one endocrine gland should be flag labeled. For the purpose of flag labelling
a model or a chart or a neat drawn diagram showing all endocrine glands should
be used.
Identification 1 mark
Location 1 mark
Hormones secreted 1 mark
Any two functions 2 mark
CHEMISTRY
Scoring method:
Aim 1 mark
Procedure/ observations 2 mark
Result 2 mark
PHYSICS
1. Convex Lens
Formula
1 mark
Procedure
1 mark
Tabulation
1 mark
Graph
1 mark
Result + unit
1 mark
2. Glass Prism
Diagram
1 mark
Procedure
1 mark
Tabulation
1+ 1 mark
Result + unit
1 mark
SCIENCE
1 mark
Tabulation
1+ 1 mark
Result + unit
356
1 mark