KENDRIYA VIDYALAYA , SECTOR-24, NOIDA (II SHIFT)

HALF YEARLY EXAMINATION (2023-2024)

SUBJECT: SCIENCE
CLASS: X1. Light energy absorbrd by chlorophyll,

MARKING SCHEME

Questio Correct Answer Marks

n
Number
Section
A
1 D 01
2 C 01
3 A 01
4 C 01
5 C 01
6 C 01
7 A 01
8 C 01
9 B 01
10 C 01
11 C 1
12 C 1
13 B 1
14 B 1
15 D 1
16 A 1
17 A 1
18 C 1
19 D 1
20 B 1
Section
B
21 Because iodine deficiency 02
leads to deficiency of
Thyroxine hormone which
causes Goitre.
22 Dendrite, cell body, axon/
nodes of ranvier, axon
endings or terminal

½x4
23 Light energy absorbed by
chlorophyll,
Which breaks down water
molecule into oxygen and 1+1
hydrogen. Light energy is
converted into chemical
energy and than reduction
of CO2 leads to formation
of carbohydrates.
24 1. pepsin- stomach, 1+1
2. trypsin- pancreas
25 Eye lens becomes too 02
curved or convex, eyeball
elongated. Corrected by
concave lens.
26 1. convex mirror- gives 1+1
larger field of view

2. concave mirror- - gives

parallel beam of light going
straight and make distant
objects visible.

Section
C
27 (A) DDR correct definition
(b) any suitable balanced 1+1+1
chemical reaction with
explanation

28 (a) medium of mouth 1+1+1

becomes acidic due to
bacteria action on food in
mouth.
 (b) heating baking soda
decomposes into sodium
carbonate, water and CO2.
NaHCO3(s)---Na2CO3+
CO2+ H2O.
Uses.. bakery product,
removing hardness of water

(c ) due to loss of water

blue copper sulphate turns
to white.

29 (a) iodine test on food if it 2+1

turns blue black than starch
is present.
(b) for proper digestion and
absorption of fats includind
the lipid soluble vitamins
also.
30 (i) v= -180/19 , -9.47 1+1+1

(ii) m=v/u, -180/19/-20

=9/19 .
h’=mh= 2.38cm
for virtual images m is less
than 1in case of a concave
lens but m is more than 1
in case of convex lens.
OR
(i) convex lens can fom a 1.5 +
real , inverted and 1.5
magnified image when
2f>u>f. it means that for an
object distance
20cm>u>10cm, the image
is real, inverted and
magnified.
Suitable ray dig.
(ii) the same convex lens
can form a virtual, erect and
magnified image when u<f,
u<10cm in present case.
Suitable ray dig.
31 (i) Retina is light sensitive 1+1+1
 screen inside an eye where
inverted, real image of an
object situated in front of
eye is formed.
(ii) pupil regulate and
control the amount of light
entering an eye.
(b) ciliary muscle contract
when viewing a nearby
object and eye lens
becomes thicker so f is
decreases & nearby object
is focused and vice versa.
32 (a) Correct definition 1,
(b) pollen/stigma, pollen 1/2x4
tube,ovule, female germ
cell
OR
Transfer of pollen to 1+2
stigma. Self and cross
pollination.any 2 points of
difference

33 (i) Gallium and 1+1+1

Caesium(Ga, Cs)
(ii) K>Na>Cu>Ag
(iii) iron reacts with steam
to produce hydrogen gas.
SECTION
D
34 (i) Biological process by 1
which an organism removes
harmful metabolic wastes
from the body. ½ x4
(ii)labelled dig of nephron
(iii) glucose, amino acids, ½x2
salts and water (any 2)
(iv) leaves play important role 1
in excretion in plants. Most of
the carbon dioxide exits
through stomata in leaves.
Many excretory products
accumulate in leaves. Plants
shed leaves to get rid
excretory products.
OR
(i) RBC, WBC, Platelets,
1
 Plasma
(ii)correct pathway of 2
oxygenated blood
(iii) valves regulates the
unidirectional flow of blood 1
from atria to ventricles( no
backflow of blood) 1
(iv) artery are thick wallwd
and blood flows at high
pressure.
Veins are thin walled and
blood flows at low pressure.
35 (i) 1. adventitious bud 1+1+1
present on leaf margin gives
rise to a new plant.
2. every cut part of planaria
gives rise to a new planaria
organism due to this
regeneration process.
3. spores are liberated and
develops into new hyphae
after reaching the ground
eg.rhizopus,Mucor
(ii) after fertilization ovule
develops and converts into 2
a seed containing embryo.
The embryo is the future
plant and when it is
provided with suitable
conditions like water, air
and optimum temperature,
it develops into a seedling.
36 (a) Correct statement 1,
(b) draw the V-I Graph and 1+1
definition of R and SI unit
of resistance is Ohm
(c ) which material is used 1+1
to make element of electric
heater and why ?
Nichrome (an alloy) with
high resistivity and high
melting point
SECTION
E
37 (a) variation is important 1+1+2
for the survival of species .
it provides resistant to
 changing environment and
makes easy for their
survival.
(b) asexual reproduction
which includes budding,
fragmentation, fission etc.
(c ) i. sexual reproduction
results in new combinations
of genes by meiosis which
esults in variation in
offspring.
ii. it involves 2 parents to
produce offspring. Hence
variability is due to diverse
set of genes of mother and
father.
38 (a) i (10-11) 1+1+1
(b) i +1
(c ) ii
(d) when acid and base
reacts to form salt and
water.

39 (a) real, inverted and small 1+1+2

size
(b) case II, a concave mirror
forms real image of same
size when object is situated
at Centre of curvature of the
mirror i.e, if u=2f. and in
case II, f=-15cm and u=-
30cm.
(c ) concave mirror of small
focal length to see large
image of teeth .
OR
caseIIIas image formed is
virtual, erect and enlarged.
Suitable ray dig.