#E l ATIES

noton

I
speed is the distance travelled
per unit time. S *
=

-velocity certain direction.

is
speedbutin a So is vector.

acceleration is the change invelocityperunit

time. a Ypt
=

ps. In case uniformly accelerating

of bodies their arg. speed is **
-

where

is
~ final
speed, is initial speed.

Graphs
·
distance-time
R 1 M

& -
d &
d objectis C constant acceleration

I
I stationary I
a speed 7
t

d deceleration

I
↳
I

speed-time
·

&
N a N

E
S S
S constant constant
&stationary
- > Speed I
> acceleration
t I

R N N
&
- S
& uniform
S S
increasing decreasing
> deceleration >acceleration acceleration
I I t

Area
*
under
graph is distance.

All objects on Earth are

pulled down to it
by gravity. As objects fall theyaccelerate

due to the force of gravity. The acceleration (g) is approx. 9.8 m/s2 & is

constant.
 R

> Free fall:no air resistances acceleration is constant. S

9.8m/s2
>
>Falling againstair resistance:
1) As body falls itconstantlyaccelerates downwards at9.8 miss has initial
speed
of No air resistance yet.
zero.
2) Air resistance acceleration net force.speed also increases.
increases, decreasing
Objectreaches terminal velocity, where weightdownwards
3) is equal to air resistance

upwards & speed is constant.

Parachute opens
4) - sudden large increase in AR. So sudden deceleration.

5) objectreaches lower terminal velocity 6) objecthits ground.

Ia*l
·

6 >
I

Ma88 & weight

>mass is a measure the
of
quantity of matter in an objectatrestrelative to

the observer.

weightis the effectofa gravitational force on a mass.

↳ w
mg
=

PS. can be rearrangedas g:

Y/m acceleration
(AKA of free fall)

-9 9.8m1s2 =
(acc. due to gravityor 9.3
Nikg gravitational field

unit mass.
strength:force of
gravity per

desity
,
density is defined as mass per unitvolume.

↳ "/v
=

if objectis irregular
an then we use
displacement to find the volume.

>
liquiddoesn'tmix
if then the liquid/solidw. lower density will float
it
higher it sinks.
 zoreg
> Forces can affect:size,
shape, direction.
speed ofa n
object.
>Newton's first IAW:

·
an objecteither remains atrest or (if moving) continues moving in a

straight line constant

at speed unless actedon bya resultantforce.

>Newton's andlaw:

· the acceleration of an objectis dependentupon net forced mass of object.

a =
/m
> Newton's 3rd law:

· for
every action there is an equal opposite reaction.

> Hooke's 14W:

f/x
force & extension so += kx or = CK is
spring constant)
·

after
limit of proportionality, spring no longer obeys hooke's law.
·

~
x
-

3
f

> Resultant
force

1) Straightline
5N
-> 50 5 + 10
-
10 N

2) Triangle method

↳ Head to tail
ION · rule

I
- A

I
-
3 N

RF ION

S
r

3) Parallelogram method.

· Tail to tail rule op.s. alwaysmake

sure force is in

De -
a direction.
correct
 >
centripetal force

· a force thatcontinuously changes the direction the

of
object, keeps it

circular
moving in a path.
·
object in a circular path is
accelerating as direction is constantlychanging

so velocityis changing. So it
is
accelerating.
·
objectmoves in a circular path
due to force perpendicular to motion

towards centre.

& I
forces
perpendicular

force is neededit:

3
·
.
a
larger
1. speed'v ofball is increased, w. mass a radius constant new
2. radius'r' b all
of is deceased, w.
speed mass constant. Important
3. mass 'm' of ball is increased, w.
speed radius constant.

·
can be relatedvia:

F mvr
=

> Friction

· Friction between 2 solids:force between a surfaces may

that
impede
motion & produce heating.

· Static friction is the maximum value of a frictional force that occurs

just as a body is
starting to move. Also known as starting friction.

·
Dynamic friction is the force acting on a body moving at a constant

speed. Dynamic friction is less than static friction.

·
Friction also acts on an object moving through air
gas-AKA resistance

· Similarly, friction (drag) acts on an

object moving through a
liquid. Drag
increases as
speed of object increases, acts to reduce acceleration & Slow

objects down.

>Turning effect / Moment

· of
moment force is a result of its turning effect.

I force
moment: x
perpendicular distance from pivot.
·
An objectis inequilibrium if there is no
resulting moment a no resultant

force.

> clockwise moment:anticlockwise moment

>centre of gravity
· The pointthrough which all of
an object's weightcan be considered to act.

· The
position of the centre of gravityofan objectaffects whether or

not topples easily.

it

>an objecttopples if centre of gravity falls outside its

base.

experiment to

I find centre of

of
gravity
irregular object

ps stability is increasedvia:
a
of
body
1) lower centre of
gravity
2) larger base area.
 momentum
·

p mv
=
(momentum:
mass x velocity)

impulse ->Ap mr-mu

=
·

↳ impulse FxAt =

·
law of conservation of momentum.
↳ momentum by collision:momentum after

↳ if
no external forces appliedtotal momentum remains constant.

·F PP/At
=

· units NS or
Kym/s

exergy work power

LE Energy
-
Many energy stores:kinetic, gravitational potential, chemical, elastic,

nuclear, electrostatic & internal (thermal),light, sound, solar.

-
Energy is transferredbetween stores

↳via .. mechanical work done;heating, electromagnetic;sound.

< RE "2 mvd
=

CPE: mgh AEp=mgAn

*
~ PS. Strain or elastic potential energy
is storedin a stretched spring,makes it
move

when released.

chemical potential energy, energy storedin chemicals that are given out

when they undergo chemical reactions.

=>
I KE energy due to motion.

Law of conservation ofenergy:energy is neither creatednor destroyed,

but it another.
only changes from one form to

energy transfer presented Sankeydiagram.

·
can be via

· can be used to calculate efficiency

Where:
useful energy (output)
->
Efficiency=
total energy (input)

power coutput)
Efficiency useful
~ :

total power (input)

↳
Energy resources

a) chemical energy from fossil fuels

fue "heats water vaporises steam rotates turbines generator generates

I &
-> -
water I forms steam turbines drives electricity

↓ I ↓ generator ↓

chemical energy ther mal potential Kinetic to

to thermal
energy
to to kinetic kineti
↓
C electric

potential

energy

ADVANTAGES

1) Always available*(not dependanton wind speed/sunlightetc)

2) Reliable technology

3) can be usedon a
large scale

4) relatively cheap

DISADVANTAGES

1) uses non-renewable energyresource

2)uses a resource, which mightbe puttowards a better
purpose
3) results in atmospheric pollution
↳ acid rain

↳ greenhouse effect

↳ global warming

b) chemical energy storedin biofuel

Biofuel dung &

->
·
fuel obtainedfrom plants or animal sewage.
↳ methane ethanol (obtained via fermentation & decomposition)
·
lead-d sulfur-free so no lead/sulfur oxide pollution.
·
Biogas is cheap to
produce on small SCALE

Butnoteconomically viable for large scale production.

Biogas reduces landfills

But due to methane content, is unstable may explode.

 c) water (energy storedin waves, tides behindhydroelectric dams)
water trapped water falls water rotates turbines generators
->
behind dam is a down throught turbines drive ->
generate

higherlevel
at pipes ↓ generators electricity
↓
↓ ke ↓
↓ ke
ke
so
greater 9PC changes O
+

gpe. to KC. electrical energy

ADVANTAGE

1) Renewable so no waste of non-renewable sources

2) No release of CO2 which is greenhouse gas causes global warming

3) No SO2, no acidrain

4) lake behind dam can be used for fishing

5) 1/ ,
"as source of water

DISADVANTAGE

1) Onlysuitable for hillyregion rainfall

we
high
2) occupies large area

3) Land has to be flooded so loss of habitat.

d) geothermal resources

Magma water vaporizes steam Turbines Generators

->
a
-
underground - forms steam rotates drive ->
generate

not substances turbines generators electricity

I
heat water ke O
↓ di ↓
+

potential pe +O Ke ke O
+

L
Ke energy ke electrical

energy

ADVANTAGES

1) renewable resource

a) doesn'tdepend on weather.

-steam

C
3)
out
No
greenhouse gases
4) Requires little
space
water in

PTO
DISADVANTAGES
1) Limitedsites

2) Harmful gases & minerals are broughtup from hole

3) Need to drill
deep holes

4) Long time to survey a build

3) very expensive, needs a

huge amountof water

e) nuclear fuel

fission turbines
nuclear water vaporizes Steam rotates generators
-> -
drive -
produces large -
forms steam turbines generate
heat generator electricity.
amounts of
d d
to heat water thermal potential to
d
↓ to
potential kinetic ↓kE KE O
+

nuclear
energy electrical

to thermal

ADVANTAGES

1) large amounts of energy from small amount of fuel

DISADVANTAGES

1) High initial costs to buildnuclear power stations

2) Difficultdisposal of nuclear waste

3)Non-renewable

4) Health risk -
can cause cancer.

5) Build up pressure maycause explosion

6) potential terroristtarget

7) provide material for nuclear weapons

f) light from sun-solar cells.

·
solar energy to electric.

DVANTAGES
A DISADVANTAGES

·
no
polluting gases · Intermittent supply

·
quiet unattractive
·

· low maintenance · takes up space

· clear · d.c. output: efficienttransmission.
not

·
permanentresource.
g) wind

Sun
-
of
KE Rotates RotateS Rotates generates
I -> -> -
wind blades of turbines generator electricity
I ↳
SO1ar solar wind mills ↓
de ↓
energy +O KE. ↓KE KE KE KE to electric

ADVANTAGES DISADVANTAGES

· No fuel burned, so no
atmospheric pollution. · Intermittent
as wind is not

·
Nothing has to be
transported always appropriate strength.
at

· No greenhouse effect visual/sound pollution

·

·
uses renewable resource · Landconsuming

· Bird injuries.

the guy-"POWERHOUSE OF
THESOLAR SYSTEM."

Sun gets energy via Nuclear fusion, where Hydrogen nucleifuse to form Helium.

scientists have been researching ways to utilize nuclearfusion, due to its great

capabilities:clean source, unlimited energy, no greenhouse gases or nuclear waste.

>Nuclear fission in nuclear powerplants.

14
I 92
I
1235
on
+
92
--
Ba
56
kr
+

36
3!n+energy.
+

energyreleased is due to the difference in mass. Suncauses wind movement.

The difference in mass is due to the mass of > waves causedby wind so

the binding energy required to keep the nucleus caused by Sun.

together as
it repel eachother. According to water cycle poweredby Sun

Einstein mass can be turnedinto Energy. refills dams - sun helps hydro-
E Act.
=
The larger the nucleus the more electric dams.

Sun-photosynthesis ->
death.
unstable it is.

fossil & pressure

tuels
+
heat
 ↳>Work

work done is equal to the

energy transferred.

:Power:Work, time, Energy:powerx time

↳ rearranged as work:
powerx time. Energy-work=fxd

MATH!W:DE

↳ unitis N.m or Joule.

w
=
fd

↳- power

power:energy/time power is work done per unit time

> Unit 5/s or W.

#Pressure
I force per unit area. P:
Y/a
>1 Pa N/m2.
=

PRESSURE
IN LIQUIDS

· Acts in all directions

Pressure:
·
pgh
· As depth 4, pressure 4

· As
P4, pressure 4.
points at level have the same is the same
· same pressure
I N CASES
PRESSURE

·
Moving gas molecules collide with walls of container.

· As theyrebound they change direction a velocity causing a change in momentum.

. P/time:force oninnerwalls of the container.

·
f(a pressure.
=
 -2 SESS
Rinetic the0
y
4) states matter
of

·
There are 3, obviously solid, liquid, gas.

↳ they are interchangeable as:

melting, exaporation
SW II 6
freezing condensation
-

#) particle model
I

sublimation

00888
solid liquid ⑧
e
⑧
08
deposition
*
intermolecular forces, as
temperature decreases

motion of particles decrease

between
particles the

spaces, their motion I

affect the properties, the lowest possible temperature, where the kinetic energy

of solids, liquids, gases of the particles is atits is

least known as absolute zero.

which is -273°C or OK.

-

> GAS PRESSURE

·
moving gas particles collide w. walls of container

·
then reboundin opposite direction so theirmomentum changes.

·
Ap/time:force on innerwalls container.
of

·
f/c pressure
=

walls.
or

BrOWNIGH mOtiOn
>

·
microscopic particles -
such as pollen grains orsmoke particles -
are seen moving randomlyin

a
suspension.
·this is due to stdl-liquid/gas molecules hitthe largerparticles randomly in fast
a
-

speed w. a lot
of momentum causing the particles to change direction.

·Since the molecules move randomly, they hitthe particles in a randomway

causing them
move in motion
to a
zigzag like
**GASES & ABSOLUTE OF
SCALE TEMD
> if maSS is fixed then

> if volume is also fixed then

·
temp &
pressure where, temp:& pressure due to more KE of particles.
else

>if
temp fixed then

·
volume a
pressure, where pressure
& vol: quice versa.

> deduction
A be
can made:PV,:Peva at constant
mass temp.
a
P

representedlike this

7
O V

·ps Kelvin oc add T(k) 0(0C) 273

to convert from to we
273 or = +

=here properties
·
solids expand the least, then liquids, gases expand the most. w. temp.

↳ Axles:used on wheeled vehicles, where axles are shrunk byusing liquidNitrogen, then

3 year wheels are slippedon them once they expand they give a
tightfit.
very

↳ Bimetallic strip: used in fire alarms, since

where copper expands more than iron

the individual metals can'tmove on their own, the iron bends to complete the

circuit ring
the alarm

Specific heat capacity

c rise in object's temperature increases its internal energy. P.S. increase in temp.
is an increase in
arg. KE all
of particles in an object.

>specific capacity is
heat energy required per mall
unit per unit temp increase.

c = AE/mo DD

is specific heat capacity

 P.S.
during change in state
energy is being inputtedwontchange in
temperature.

zea288ea of themal energy

Tr Cn Sf et

conduction >radiation
W
-
convection aka infrared, emitted
-

whole material gets in liquids [ by all objects.

warmer via vibrations 9aSeS ·
doesn'trequire medium

-> mainly metals fluidheated so · for objectto be constant

at

due to mobilee expands, so becomes temp. Itmust transfer

↳ liquids, gases less dense so rises energy away from object at

are bad this as
at A.Cs are puthigher same rate it recieves it.

particles are far up so cooler airsinks ·

Black & dull surfaces are

apart , no free e &cools whole

room better absorbers emitters
vice versa w. heaters. of radiation than shiny, white
white/shiny surfaces are better

reflectors of radiation.

Black emits more radiation

when not.

Only short-wavelength radiation

like that coming from sun can

penetrate glass & CO2[ CH4,

but radiation from Earth has a

longerwavelength & Can't

penetrate these gases strap heat.

Saucepans are
that
polished
are poor emitters, keep heat
for
longer.
 - S
general properties
Waves transfer energy w.outtransferring matter.

Waves
-
L ↳

Need
yes medium? no
vibration
I
↓ ↓ ↓ ↓

Mechanical Electromagnetic Longitudinal Transverse

·
sound water I vibration
~

vibration

is
parallel to perpendicular
direction of wave to direction of

i
propagation wave

·
such as
propagation.
Seismic, ·
light, water E
sound waves displacement seismic
crest S.

I particles,
of
amplitude
Frough
-
compression Larefaction
Funere turnere
particles are particles are

closer together further away

I high pressure from eachother

a low pressure

distance
· between compression

& successive compression or

rarefaction successive
rarefaction is wavelength. X.
frequency
:
N o. of waves passing in a second.:Hy wave/second
f = no.
of
waves/time/s f
=

'/T
=

<periodic time:time needed for one

complete wave to
travel

T:"f:time/no. waves.
of

<
speed:v xf
=

Waves can
undergo reflection at plane surface

i
crT
2: Li Lu law ofreflection
=

Boundary
a ffectX,v
doesn't orf direction
just

waves can undergo refraction:

happens due to change in speed (when travelling through
mediums of densities (
different

·deeD shallow in water deep shallow deep

S -
7

since

normal
along

no
change
-ente
in direction not normal in shallow the
along so

refractedray moves towards normal E v.V.

a waves can undergo diffraction through gap

diffraction through diffraction through
t
n small gap less than or

E
-5
↳
irg. gap- X.

g
equal to wavelength
-
less diffraction.
the
larger the
gap the

the larger the more diffraction.

>the lines drawn are calledwavefronts which we can see while looking at surface of

water from above. Theyare the successive crests that

join.
 siget
transverse waves travel
that in straight lines.

>
speedof lightis 3x108 m/s

↳ always constant

#Reflection
light
of

·
the normal: imaginary line perpendicular to the pointin which incident ray strikes surface.

Ray diagram

Step 1:draw incident

ray anywhere Step 2:draw reflected ray(i (r =

on mirror

mirror

= mr? s

Step 3:draw
another Step 4:reflectand ray
incidentray

e.25x
its
h
S

image,
Step 4:extendreflected

rays an characteristics of mirror image

· Virtual

in · Erect

↳
h
S di · same
size
W
W · Behind mirror

· inverted
↳=)Refraction

Bending of lightas it
passes from one medium to another is calledrefraction

Angle refraction
of is angle between refracted rays normal.

from rare to dense ray bends towards the normal.

from dense to rare, the ray bends away from normal.

it
lightray passes perpendicular to the surface is
passes underiated.

rare to dense dense to rare

· A
decreases ·
A increases

·
wave speed decreases ·

speed increases

frequency unchanged .
unchanged
bends towards normal bends away from normal

Li (refraction. i refraction

-
T

E
>
7 >
~

-
~
GLASS BLOCK TRIANGULAR PRISM

SEMI-CIRCULAR BLOCK

GLASS BLOCK

object
-image
of

RAU DIAGRAM

-water EXAMPLE

↑object
 refractive index is ratio of wave speeds in a differentregions.

n
1 or =
speed lightin air
=

of

sin r
speed lightin
of
mediL

>critical angle:is the Li from denser medium that causes an

angle refraction
of of

900.

↳n =Ysinc c is critical

> it (i >, total internal reflection inside denser medium. No refraction in

air.

can be usedin periscopes.

D
a
454
At pointa ray falls perpendicular to surface,so it

passes underiated.
-
critical of this type of is 420
angle glass
At b Li is 450, SO TIR. 9 so on.

7 ⑳
· And optical fibres.

usedin telecommunication where:

digital signals encodedas pulses

↳
are

of lights are sentby a transmitter.

flexible & transparent light pulses travel through optical

fibrecable as
they undergo multiple

total internal reflections in optical

fibre cable.

lightsignal is decoded by a reciever at far

end optical
of fibre.
 Lenses
↓ ↓
Diverging
converging C
-

.
·
has the
action ofrefracting rays falling
on it to collectthem a
at
point.

↓principle
focus

principal
"ocal optical
8

a xiS
length
centre

·Principal axis:line passing through the

optical centre

& perpendicular to the lens surface.

principal focus: pointon principal axis of a lens to which

lightrays

parallel to "
"converge, or appear to

diverge from. AKA

focal point
·Focal length:distance between the optical centres the principal
focus ofa lens.

me
Spossibilities
d formed
objectat Between F42F
~
2F
object beyond ·
enlarged real

↳ 2F ·inverted
img 2F
at beyond
- 27

real, inverted, ↳
image between

same size F427, real, inverted,

diminished.

-> optical
objectbetween F centre

↳ img same side lens

of as object,
image, upright, larger.
↳ rays extrapolated backwards

I doesn't
form visible projection at

screen
 Sight
problems
↓ n

be
long-sightedness
can see distantobjects but
E can see
short-sightednes
close
up objects
not close objects. clearly
G meet behindretina
↑

(image cannot DISTANT OBJECTS

E
-

rays see

focused behind retinal because image is formed

↳ can be b.c eyeball or

is too short in front of retina

lens cannotbe made thick enough.

b usually b.c
eyeball too
long or

↳ rays can'tbe converged enough lens be

cannot made thin enough so

to meet on retina. rays meet in frontof retina

CONVERCING LENS USED DIVERGINO LENS USED

↓to make rays from distantobject

diverge lens
so that is able to

form a focused image.

DISPERSION L IGHT
OF

N
white light -> Red When white light falls on a triangular
~
orange increasing increasing prism, dispersion occurs where colours in

~
Yellow ↓
frequency spectrum are separated. Each colour has

~ Green different, so each has differentn.

greatestfor red.
↑
BI4e n is violet lowestfor
-
indigo violetis retractedmostby prism.

~
violet -

visible lightw. A frequency is monocromatic.

21 colour is 1 frequency)
exectsona spectrum
gretic
a
U rays transverse waves which transfer energy

ways
·x increasing increasing · All travel w. same speed in vacuum

·ultraviolet X f 3.0x108 m/s.

.
visible light all obey v=df (rconstant so
if changing)
· infrared the higher the flowerthed the greater energy is

·microwaves transferred

. radio - combination of electric a magnetic fields directed at

from
rightangles eachother

Uses of EM waves

· RADIO:radio & television transmissions,

astronomy, radio frequency

identification (RFID)

· MICRO:Mobile phones, satellite television,

microwave ovens

->
may cause internal
heating of body tissue.

·INFRARED:electric grills, short range communications such as remote controllers for

↑elvisions, intruder alarms, thermal imaging, optical fibre.

I may cause skin burns intensity is high.

if

·VISIBLELIGHT:vision, photography, illumination, communication (optical fibres)

ULTRAVIOLET securitymarking, detecting fake bank notes, sterilizing water

↳ damage to surface cells eyes, leading to skin cancer seye conditions.

X-RAUs:medical scanning a security

scanners
↳ cancer, mutation, damage bodycells

U-rays:sterilizing food medical equipment, detection of cancer & treatment.

↳ mutation, cancer, damage body cells

 Communication

L
W
d ↓
Satellites a Bluetooth
geostationary WiFi
optical
ow
↓
Earth orbit · mobile phones short range fibres

·
much closer E arth at
Orbit 5 wireless internet communication. VISIBLE

2000km above the same rate Use MICROWAVES RADIOWAVES OR INFRARED

Earth. Earth rotates. b. C. they

can b.c. can pass cable tv. 9
little to no delay so stay above
penetrate some through walls high-speed
so suitable for convos. pointon
I Earth's walls only butsignal is broadband

· a hrs to orbit surface. require a weakened. b. c glass is

HOWEVER.
· ↳35000km above Earth shortaerial transparent to

only cover
small, above Equator for transmission visible light
area so lots can transmit large I reception. I some infrared;can

are needed. AMOUNTS of data, so high rates

carry

·
phones use this used for satellite T.V of data

& satellite
phones. directbroadcast
-

·HOWEVER waves
-

travel long DISTANCES

so slightdelay, so unsuitable

for conversations.

communication w

artificial satellites

is mainlyby

MICROWAVES
 DATA SIGNALS
D

I
↓ ↓

Digital ↓ Analogue
W

·
only discrete CRAPH GRAPH

values, high 9 ~features:

10 W
8
I .

voltage can be varied

3 smoothly can have

I
switches, Digital meters, (pplayers, variable resistors, any value w.in range.
telecommunication analogue meters I continuosly vary

Any signal gets distorted

Butdigital is easier to repair.

. ADV. OFDIGITAL OVER ANALOGUE

1) clearer
~

2)
/

A rate of transmission

3) a
range:sentover longer distances due to more accurate

regeneration. (less affected noise)

by
S

Easily processed I
4)
can deal w.computers &
 o
an
so

· producedby vibrating objects

↳ require a medium to travel

I longitudinal waves ->

compression rarefaction
->
series compressions &
of rarefactions where molecules vibrate

parallel to direction of wave propagation

of sound
·
speed
Air:330 mIs 5>2>6

water:1400m/s
a
speed as tempe
solid:5000m/s "we can only near from 2013-20,000 Hy

· Reflection

· can be reflected, causes echo, direction

only is affectedby reflection

I can be used to measure speed. S: "travelled/ time:I taken to hear echo.

·
Pitch loudness
loudness ->
amplitude

>pitch -
frequency

ultrasound

>soundw. frequency higher than 20 kHz.

-> sonar

·measure depth of water

-
pulse of ultrasoundis sentdown from a boat reflects
from seabed.

time taken for pulse to be recieved is measured.

-> Material testing

a detect flaws inside materials (small crack in metal girder could cause collapse
of a building).

->
medicine

c ultrasonic waves partially reflectedfrom boundaries between diff. materials.

computer analysis reflected

of waves produces an
image.
 # CRIIC
m
magnetic
MAGNETISM

~ V -

Magnetisation Magnetic
Magnetic E
methods I fields
stroking
-> steel bar
non-magnetic from North to

Electric induction strokes materials south.

-> formed from - when piece magnet · direction of

I
a coil of wire of magnetic using same magnetic non-magnetic force on ou

through which material is pole in same materials materia Is pole a

of

an electrical Broughtneat direction are those cannot be magnet

currentis pole permanent

of thatcan magnetised d

6.5
passed magnetitbecomes be magnetisedaren'tattractedo
.
can be switched a magnetitself by a magnet; by magnet

on 90ff. attractedby
↳nur
·

Strength can be
magnetin

increasedby un magnetised .
force between

L state. 2 magnets is

↑ currentw a resultof

L I hard
↑ no Soft interaction of

↓
of turns on
permanent their magnetic
soil +
emporary magnet fields.

↓ Steel
righthandgrip rule magnet
used to findmagnetic ↳ Eg. electromagnets ↳ credit cards,

field used for: compass, computer harddisk;

·electric bells microphone, generator,

magnetic locks motOr

a
·motors

·generators
 electsoftating

ELECTROSTATICS

I
↓
- -
CONDUCTOrS E Quantity
inSHIatOrS of charge Electric field

> insulators

conductors
W
have
e-tightly Ineasuredin Definition

have free bound to their conlOmbs region of

space
where 9 ne-
moving atoms. where an electric
=

=
10
1.6 x 192
-

i
charge

methods
charging experiences ~Direction

charging a force direction of

by rubbing charging bycontact due to 0. force On d

charged body charges. . +Ve ChArde

Touches uncharged 1
1
-

body. They share

t
+

< 7
I
charge.
↳ ~
V

v
> >
L

t > -

- -

-
7 - -

I -
t M
-

s
7
I -

etectioic
quantities
current

>electric currenti s related to the flow of charge.

>Effects a
of current:Heating lighting. Magnetic Chemical.

I G/unitampere.
=
1C=1 As

conventional
I
currentflows from the to-ve.

Directcurrent:e-flow in
> 1 direction only.

> Alternating current:flow reverses regularly

I cycles, alternations in 1
frequency no. of sec.
:
 voltage
>E. m.f:electrical work arounda
done by a source in
moving a unit
charge complete
circuit.

= Y/a
=

or v E/0
=
->
measuredin volts.

p.d:work done by a unit charge passing through a

component.v WQ =

Resistance

&R YI
=

opposition of current

M
I constant N
increasing R
I
I
resistance

> 3
V V

t filament
Thermistors' resistance decreases lamp

as rises.
temp.
·
LDRS resistance decreases when

lightintensity increases
>Resistance wire
of is a
length q a'lared of cross-section 4 x'd2
& depends on type of wire

0 P IV=

· E IV t
=

kilowatt-hour is
·
the electrical energy used by a 1kW
appliance in 1 hus.

1kWh 10005/5 =
x 3600 S
 circuity
electric
·I

fuse variable thermistor

-
resistor
>
->

light-dependent diode LED

resistor

M
6 -

generator heC+ e i 10 TO r
potential divider

32 m

transformer magnetic coil

relay
coil

componentthatallows
Diode:circuit passage of in
current one direction

not
but the opposite.
has high resistance in backwards direction a low R inforwards direction.

>made from semi-conductor

I forward bias-current flows in circuit.

~ reverse bids-diode blocks current flow.

↳ acts as rectifier for A.C.

efacing the
Le usedin chargers to allow to
current n otfrom
flow to but battery

i
=
->

A ndio 3

Ratio of voltages across a resistors

~
 SERIES
currentsame It I, I2
=
=

voltage shared Vt V,
=
+ V2
·
resistance total:R, +R2.

Parallel

·
Vsame Vt V, V2
= =

·
R1 R,xR2/R, R2
=
+

·
It 1, I2
= +

Sacurrentgoing
·

to junction is equal to total leaving.

current

<advantages of lamps in parallel

1) fixed p.d. So each shines w. same brightness
lamp
2) each lamp can be turnedon doffindependently
WLEARR
 earth
SSACE
<Earth rotates on its tiltedaxis once every 24hrs.
->
creates day for half the Earth's surface & night forthe other.

I causes sun to have an apparent daily motion fromEast to West

t akes
<It the moon
approximately one month to orbit the Earth. Andrevolves along

its own axis in the same time. So we only

see one side of the moon.

we see the moon byreflected sunlight. 2 of it is always illuminated by suk.

its position relative to Earth changes the wayit appears. As moon moves, the shape t he
of

lightpart changes.

seems to rise from East to west. due to Earth's rotationabout its axis.

average orbital
speed.
solar system
s tar - asteroids;
sun;8 planets;
ets; orbiting
consists of 1 comets,moons

planets. minor planets

·
Planets inorder:mercury, Venus, Earth, Mars, Asteroid belt, Jupiter, Saturn, Uranus,

N
ep+ Ye, DI4tO.
Asteroid:any butdoesn't for
·

objectthatorbits a star, have enough mass gravitational

attraction to have pulleditinto a spherical shape.
Dwarf planets:(larger asteroids) have
enough mass to be spherical, butnotenough to

attract clear area around them of smaller objects.

>Planets & minorplanets have elliptical orbits a sun atcentre
isn't of orbit
unless

approximately circular. (large planets)

4 comets have extremely elliptical orbits a speed whentheyreach the
up sun a
slows down when it moves further away. Energy is conserved w. some the
of KE

it
has whenclose to the Sun being transferredinto potential energy as it
moves

away.
The total energy (gravitational potential and kinetic energy) of an object in orbit is conserved; [1 mark]
Gravitational potential energy is proportional to the object's distance from the surface of the Earth; [1 mark]
Therefore, when an object is closer to the Earth, its gravitational potential energy is lower, so its kinetic energy must be
higher; [1 mark]
Kinetic energy is proportional to velocity squared, so if kinetic energy is larger, velocity will also be larger; [1 mark]

> Formation solar

of system
1) Itall started with anebula interstellarclouds hydrogen
of & dustthatwere pulled

togetherbygravityin region
in
space highestdensity.
of

2) protostarformedatcentre

3)material left over from hebuld rotatedaroundSun

4) small particles attractedeach other to form largerones a grow in size -

accretion

↳A is -
rotating accretion disc thought
to have formed planets formedhere.

-> all planets have similarplate a revolve aroundSun in same direction.

·heavierelements from explodingsupernord. Sun->2** star

Get
3) As Sun become bigger it become hotter. So lightmolecules couldn'texistin solid
State (methane, water 9 so on). So innerplanets made from
high up materials.

v. V.

6) Asteroidbelt - leftover pieces of rock

=>Accretion ->
coming together matterunderthe
of influence of pravity to forth larger
bodies.

>Earthis approx. 150,000,000km away from SUD.

The furtheraway an or is from the Sun the longerits orbital period
the lower its
temperatured lower
p
The smalletthe mass, the smallerthe surface gravity.
Gravitational attractionkeeps objects in orbit around SLR.

↳ 98% mass
of so planets orbit
sun.
 starg
>Sun releases mostof
energy in infrared, visible , u.v regions. They get
energy
via nuclearfusion Hydro getinto Helium
of

1solar mass- sun

mass of 2x1630kg
=

> Stable stat:statthat

is not
collapsing expanding
or b.c. force of gravity is

balanced by radiation pressure still has a of

lot H to fuse.

Plasma: completely ionizedgas inwhich temp is too high forneutral

atoms to exist
so consists
it of estrely charged nuclei.

7 lightyear:9.5 x m
1015

>Life-cycle ofStar:

1) Stat
is formed frominterstellat clouds of gas, dust contain
t hat hydrogen.
2) a protostatis interstellarcloud
an collapsing increasingin temperature
as a of
result its internal gravitational attraction.

3)a protostatbecomes a stable statwheninward force of gravitational

attraction is balancedby an outward force due to high temp, in centre of

stat.

4) Then becomes
it estable main sequence stars fuses H to He to provide
energy.
eventually
5) stars run out of H