Download Foundation - GCSE Science Revision

OCR GCSE
Physics
Homework Mark Scheme
P5a&P5b Foundation & Higher
8
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OCR GCSE
Physics
5
P5a Orbits
Foundation
1
2
3
4
5
(a) a satellite is an object that orbits a
larger object in space
[1]
(b) an artificial satellite has been man
made whereas a natural satellite has been
formed by nature
[1]
(c) the Moon, any man-made satellite
e.g. Metostat
[2]
centripetal force, it acts towards the
centre of the circle.
[2]
force due to gravity
[1]
but a better answer would be:
the gravitational force provides the
centripetal force
[2]
(a) the gravitational force, provides the
centripetal force, needed to keep the
shuttle and satellite in a circular orbit
[3]
(b) the time period will get longer
[1]
(a) answer same as 5(a) higher
[any 5]
(b) answer same as 5(b) higher
[3]
(c) answer same as 5(c) higher
[any 6]
Higher
1
2
3
4
Homework Mark Scheme
P5a&P5b Foundation & Higher
force due to gravity
but a better answer would be:
the gravitational force provides the
centripetal force
(a) Size of each mass, distance between
the masses.
(b) It is a quarter as strong.
Sketch of an ellipse with the Sun at one
focus, arrows moving towards and away
from Sun
(a) point nearest to Sun labelled fastest,
point furthest from Sun labelled slowest
(b) somewhere on part of path moving
away from the Sun labelled gravitational
force decreasing
(a) the gravitational force, provides the
centripetal force, to keep the shuttle and
satellite in a circular orbit.
(b) mass gets less, therefore the
gravitational force gets less
(c) gravity gets less because of
greater distance. Time period gets
longer
[1]
(a) answer should include: geostationary
orbits are: higher, always above the same
point on the Earth’s surface (NOT
stationary above Earth), time period is 24
hours, always above the equator
polar orbits are much lower, gradually
pass over all the Earth, time period only
a few hours, goes over both poles.
[any 5]
(b) transmitters and receivers only need
point to one position in the sky, possible
to transmit information between two
points on the Earth 24 hours a day, only
require three satellites to cover the whole
of the Earth.
[3]
(c) Geostationary
Polar
communications
weather
e.g. TV, radio, telephone military
weather forecasting
e.g. spying
GPS
Earth watch
e.g. land use, ice
cap etc
[any 6]
(d) 35 800 km
[1]
(e) Lower orbits mean the gravitational
force is greater, therefore the
satellite has to travel faster.
[2]
P5b Vectors and
equations of motion
Foundation
[2]
[3]
[1]
[1]
[1]
[1]
1 (a) 2 m/s (b) 8m/s
2 speed only has a size
velocity has a size and a direction
3 (a) 8 N to the right
(b) 80 m/s to the left
(c) 50 N to the right
4 40 m/s
5 24 m
[2], [1]
[1]
[1]
[2]
[2]
[2]
[4]
[4]
Higher
[1]
[3]
[2]
[2]
1 264.8 m/s
bearing 190.9º/angle 10.9º
2 speed only has a size
velocity has a size and a direction
3 (a) 8 N to the right
(b) 80 m/s to the left
(c) 50 N to the right
4 24 m
5 300 m
[2]
[2]
[1]
[1]
[2]
[2]
[2]
[4]
[4]
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OCR GCSE
Physics
Homework Mark Scheme
P5c&P5d Foundation & Higher
P5c Projectiles
Foundation
1
2
3
4
5
6
diagram showing a parabolic path
parabola
any list of 10, e.g. golf balls, javelin, etc.
gravity
because there are no horizontal forces
because the force of gravity acts
vertically downwards
[1]
[1]
[5]
[1]
[1]
[1]
Higher
1
2
3
4
5
6
7
8
3
4
gravity
there is no horizontal force
because gravity only acts downwards
80 m
(a) 3.2 s
(b) 18.75 m/s
(c) 32 m
time to fall = 0.63 s
horizontal velocity = 31.6 m/s
resultant velocity = 12.2 m/s
angle = 55°
(a) 80 m
(b) 40 m/s
(c) 20 m/s
(d) 44.7 m/s at an angle of 63°
[1]
[1]
[1]
[2]
[2]
[2]
[2]
[1]
[2]
[2]
[2]
[2]
[2]
[2]
[4]
P5d Force and
momentum
Foundation
1
2
(a) action of man on scales, reaction of
scales on man; it will be a bonus if also
action of scales on floor and reaction of
floor on scales
(b) two sets of action and reaction pairs,
one pair between beam and rope and one
pair between rope and weight.
(c) two sets of action and reaction, one at
each end of the rope between the boy and
5
6
7
[2]
[2]
[2]
[2]
[1]
[4]
[2]
[2]
[1]
[1]
[2]
Higher
1
2
3
4
5
6
7
[2]
the rope. Some may draw the action and
reaction between the boys and the
ground
(d) action of gases coming out of the
back of the rocket and the reaction of the
these gases on the rocket
explanation of any type of bat and ball
collision, e.g. cricket bat and ball. The
ball exerts an action on the bat and the
bat exerts an equal and opposite reaction
on the ball
one car exerts a force on the other car
and the second car exerts an equal and
opposite reaction on the first
mention should be made of seatbelts,
crumple zones and airbags. How each of
these increase the time over which an
accident occurs and this decreases the
acceleration (deceleration) and therefore
reduces the force on the passenger
rapid acceleration must mean a large
force on the body and therefore the risk
of injury
mass and velocity, if either increases
then momentum increases
(a) 48 000 kg m/s
(b) 16 000 kg m/s
(c) longer time period and therefore less
acceleration and less force
same as in Q1 foundation
same as in Q4 foundation
same as in Q5 foundation
(a) 48 000 kg m/s
(b) 16 000 kg m/s
(c) 8000 N
3.25 m/s
5 m/s
gases exert an equal and opposite
reaction on rocket, gases have a large
velocity, therefore have a high change in
momentum backwards, this must be
equal to the change in momentum of
rocket forwards.
3 of 15
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[8]
[4]
[2]
[2]
[2]
[2]
[3]
[3]
[4]
OCR GCSE
Physics
Homework Mark Scheme
P5e&P5f Foundation & Higher
4
P5e Communications
+
radio wave
(carrier wave)
Foundation
1
(a)
[1]
=
3
(b) diffraction
(c) they are reflected
frequencies above 30 GHz
absorbed by gases and rain, scattered by
dust
they are transmitted to a satellite
that retransmits it back to Earth
[4]
[1]
[1]
Foundation
1
[2]
[1]
[1]
2
3
2
1
4
transmitter
5
4
they are both electromagnetic waves,
both transverse
microwaves higher frequency, radio
waves diffract in atmosphere, radio
waves reflected off ionosphere
[2]
6
[2]
Higher
1 Frequencies above 30 GHz
absorbed by gases and rain
scattered by dust
2 They are transmitted to a satellite
which retransmits it back to Earth
3 Radio waves are diffracted more
because of longer wavelength
[1]
[2]
[1]
[1]
[1]
[1]
[1]
[1]
[1]
[1]
P5f Interference
satellite
receiver
amplitude
modulated
radio wave
sound wave converted to electrical signal
is added to an EM wave called the carrier,
receiver has a circuit to recover signal
hill
2
sound wave
(changed into an
electrical wave)
they interfere, if trough meets a trough or
a crest meets a crest then a large wave is
produced, but if a trough meets a crest
then no wave motion is observed
[3]
we need a very narrow slit, about the same
size as the wavelength of light, width of
door is too great
[3]
(a) rotate a sheet of polarised glass/plastic
in front of windscreen, and it should go
from allowing light through to no light
[2]
(a) transverse vibrations, in all directions
[2]
(b) place one sheet of polariser in the
path of the light.
[1]
they interfere, if trough meets a trough or
a crest meets a crest then a loud sound is
heard, but if a trough meets a crest then
no sound (silence) is observed
[3]
(a) if the same frequency they could
interfere and produce no signal
[2]
(b) if the same then the incoming signal could
interfere with the transmitted signal
[2]
only waves cause interference
[1]
Higher
1
2
3
5
same as Q3 in foundation
[5]
loud note produced by troughs arriving with
troughs and with crests arriving with crests,
in phase, constructive interference, path
difference a whole number of waves
[4]
silence produced by trough arriving with a crest,
out of phase, destructive interference, path
difference an odd number of half waves
[4]
same as Q5 foundation
[4]
same as Q6 foundation
[1]
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OCR GCSE
Physics
Homework Mark Scheme
P5g&P5h Foundation & Higher
(b)
P5g Refraction
Foundation
Strictly speaking the phrase ‘total
internal reflection’ does not appear
in the foundation specification and
so questions 1(c) and 4 could be
answered without reference to TIR.
1
2
optical fibre
(c) must be travelling in the more dense
medium, must be incident at an angle
greater than the critical angle
(a) bends, refraction, speed
(b) more, dispersed, blue, red
(c) critical, totally internally reflected,
critical, fibre, endoscopes
(a)
angle of incidence
[3]
[3]
[5]
[3]
angle of
refraction
3
[2]
(b) it slows down
(c) towards the normal
(d) the refractive index
(a)
Higher
1
2
3
4
5
6
same as Q2 foundation
same as Q3 foundation
same as Q4 foundation
n=2
19.5º
when the fibre is in air the critical angle
in the glass 41.8º (sin C = 1/1.5),
when the fibre is in water the critical
angle in the glass increases to 60.1º
(sin C = 1.3/1.5)
[1]
[1]
[1]
[2]
red
white
light
4
blue
(b) each colour travels at a different
speed or has a different refractive index
(c) dispersion
most
(a)
[2]
[1]
[1]
[3]
refracted
air
glass
little
reflection
Less than critical angle
air
glass
Equal to critical angle
air
glass
all reflected
Greater than critical angle
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5 of 15
[2]
[2]
[4]
OCR GCSE
Physics
Homework Mark Scheme
P5g&P5h Foundation & Higher
P5h Optics
Foundation
1
lines converging from both lenses
focal length shorter for fatter lens
[2]
[1]
F
F
2 coming together
3 (a) object between f and 2f of lens
(b) object closer than f of lens
4 distance between lens and film changes
[1]
[1]
[1]
[1]
Higher
1
2
3
(a) object between f and 2f of lens
(b) object closer than f of lens
distance between lens and film changes
(a) suitable diagram
[1]
[1]
[1]
[2]
convex
lens
6.7 cm
1.5 cm
2.5 cm
F
image
object
4 cm
2.5 cm
2.5 cm
4
(b) 5.5 cm, 2 cm high
(c) object closer than 2f
50 cm by 25 cm
[2]
[1]
[2]
6 of 15
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OCR GCSE
Physics
Self-assessment quiz: answers
P5a Foundation and Higher
Orbits and satellites
1
Fill in the gaps below using the words from the list:
geostationary
communications
polar
greater
[F/H]
lower
imaging
gravity
The Moon, just like man made satellites, orbits the Earth due to the force of gravity.
The higher a polar satellite’s orbit the greater the orbital period. A geostationary
satellite remains in a fixed position above the Earth’s surface. An example of a satellite
that uses a geostationary orbit is one used for communications.
2
True or false? Put T or F in the boxes
The higher the orbit the faster a satellite travels.
Imaging satellites are in geostationary orbits.
A geostationary satellite orbits the equator in 24 hours.
Gravity provides the centripetal force for orbital motion.
3
[F/H]
F
F
T
T
There are a number of errors in the following paragraph. Spot them and correct them in
the space below.
[H]
The force of gravity can explain the orbits of planets and their satellites as well as
objects such as comets. As a comet gets closer to the Sun its speed increases as ice
melts and its mass decreases. The orbital period of a satellite (how fast it travels around
the planet) increases with the distance from the surface. Low polar satellites orbit in
many days as the force of gravity is greater closer to the planets. Satellites do not fall to
the Earth because gravity keeps them moving at an approximately circular orbit.
(a) A comet’s speed increases as the gravitational force increases.
(b) The orbital period is the time taken to orbit.
(c) Low polar satellites orbit in a few hours.
(d) Satellites do not fall as their tangential motion keeps the orbit circular.
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OCR GCSE
Physics
Self-assessment quiz answers
P5b Foundation and Higher
Vectors and equations of motion
1
Complete the following crossword by filling in the missing words below to find an
acronym for equations of motion.
1
2
D
E
C
V
A
E
I
Q
3
4
S
5
2
L
C
S
U
V
A
T
T
A
E
R
O
A
T
L
[F/H]
N
I
O
C
O
C
E
N
I
S
T
Y
R
1
Distance can be calculated by multiplying the average velocity by the time.
2
There are four equations of motion.
3
Velocity is speed in a given direction.
4
Mass and temperature are scalar quantities.
5
Force and velocity are vector quantities.
The equations of motion are often known as the ‘suvat’ equations because
s stands for DISTANCE measured in metres (m).
u stands for ORIGINAL VELOCITY measured in metres per second (m/s).
v stands for FINAL VELOCITY measured in metres per second (m/s).
a stands for ACCELERATION measured in metres per second squared (m/s2)
t stands for TIME measured in seconds (s).
3
Are the following statements true or false? Put T or F in the boxes.
Speed is a measure of how fast an object is moving.
Direction is important when measuring speed.
If two cars approach each other on a straight road then their relative speed
decreases.
Average speed can be calculated by multiplying the total distance travelled by the
time taken.
In vector quantities direction is important.
4
[F/H]
[F]
T
F
F
F
T
A car starting from rest steadily increases its speed up to 20 m/s in 5 s. How far has it
travelled?
[F/H]
s = (u + v)t/2
s = (0 + 20)5/2
answer = 50 m
5
A body with a velocity of 4 m/s has an acceleration of 5 m/s2 for 10 s. What is its final
velocity?
[F/H]
v = u + at
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OCR GCSE
Physics
Self-assessment quiz answers
P5b Foundation and Higher
v = 4 + 5 x 10
answer = 54 m
6
A car starting from rest has an acceleration of 4 m/s2. How long does it take to travel a
distance of 200 m?
1
[H]
2
s = ut + /2at
200 = 0 + 1/2x4 t2
t2 = 200/2
answer = 10 s
7
A body with an initial velocity of 10 m/s has an acceleration of 2 m/s2. What is its
velocity after it has travelled 11 m?
2
[H]
2
v = u + 2as
v2 = 102 + 2x2x11
answer = 12 m/s
8
Draw lines between the boxes in the left-hand column and the correct answer in the
right-hand column.
The resultant of two
parallel vectors travelling
in the same direction is…
equal to the difference between the
two vectors and in the direction of
the largest vector.
The resultant of two
vectors at right angles to
each other is…
VR2 = Va2 + Vb2
The resultant of two
parallel vectors pointing
in opposite directions is...
equal to the sum of the two vectors
and is in the same direction as the
original vectors.
The resultant of two
vectors at right angle to
each other can be
calculated using the
equation…
equal to the diagonal of the rectangle
drawn to scale using the vectors as
the sides of the rectangle.
[H]
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OCR GCSE
Physics
Self-assessment quiz: answers
P5c Foundation and Higher
Motion of falling objects
1
Fill in the gaps using the words from the list
horizontal
constant
accelerating
[F/H]
air resistance
force
increases
When we talk about the velocity of falling objects we ignore air resistance. If this is
ignored then the only force acting on the object is gravity. The horizontal velocity of falling
objects is constant and the vertical velocity of the object increases. If the object’s speed
increases we say it is accelerating. As gravity only acts downwards it has no affect on the
horizontal velocity of the object.
2
A boy drops a stone from a bridge over a river and his friend throws a similar stone
horizontally into it at the same time.
[F/H]
Complete these sentences:
(a) We say that the thrown stone has constant horizontal velocity because we ignore air
resistance.
(b) Both stones hit the water at the same time because the only force on both stones is
gravity.
3
The following sentences regarding projectiles have been mixed up. Connect them up so
they make correct statements.
[H]
The resultant velocity of a
projectile
in the horizontal direction.
Near the surface of the Earth
is the vector sum of the
horizontal and vertical velocities.
There is no acceleration
the gravitational field is uniform.
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OCR GCSE
Physics
Self-assessment quiz: answers
P5d Foundation and Higher
Momentum
1
Fill in the gaps using words from the list. Choose four different words from the list.
force
energy
momentum
movement
acceleration
increase
[F/H]
decrease
If you multiply an object mass and velocity together you calculate a property called
momentum. Sporting injuries are often caused by a rapid acceleration of parts of the body.
Crumple zones reduce injuries as the force of a collision is reduced. This is reduced
because as the zone crumples it increases the time of the collision.
2
Solve the clues across. The shaded column is a word that is central to this item.
6
V
E
2
3 C R
4
5
L O C
7 R E
8 T
1
F
U
S
I
I
D
I
M
O
M
E
N
T
U
M
A
R
P
A
J
Y
C
E
S
C
L
T
U
S
E
E
E
S
R
[H]
Y
1
The more of this an object has the more momentum it has.
2
Reducing this in collisions reduces the chance of serious damage to passengers.
3
This zone absorbs the energy during front or rear end collisions.
4
What type of belt stops passengers colliding with hard surfaces on the dash board.
5
This is reduced when air bags are deployed.
6
Reducing this slowly reduces deceleration.
7
Spreading the change in momentum over a longer time does this to the forces in
collisions.
8
All safety features increase this during collisions.
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OCR GCSE
Physics
Self-assessment quiz answers
P5e Foundation and Higher
Long distance communication
1
Complete the following crossword.
1
8
2
3
R
[F/H]
A
D
I
O
2
I
O
N
O
S
P
H
E
3
R
E
F
L
E
C
T
I
O
N
4
5
D
I
F
F
R
A
C
T
I
O
A
E
R
I
A
L
6
G
A
P
7
M
I
C
R
O
W
A
V
E
S
S
C
A
T
T
E
R
E
D
R
E
N
1
These waves are very suitable for broadcasting.
2
Radio waves can be reflected off this part of the atmosphere.
3
This occurs when light hits a mirror or water waves hits a hard surface.
4
This occurs when a wave travels through a narrow gap.
5
Radios require one of these to collect radio signals.
6
When this gets bigger then the amount of diffraction gets less.
7
Satellites use this type of wave for communication.
8
This happens to some electromagnetic waves when they meet dust.
Answer these questions True or false. Put T or F in the boxes.
[F/H]
Radio waves of frequency below 30 MHz can be reflected by the ionosphere.
T
Radio waves cannot be diffracted around the curve of the Earth.
F
Radio waves have a longer wavelength than microwaves.
T
Satellites use radio waves and not microwaves for communication.
F
Explain what is wrong with the following statements:
[H]
(a) Microwaves are sent as thin beams because they have long wavelengths.
They have a short wavelength and only diffract a small amount.
(b) Minimum diffraction occurs when the wavelength equals the size of the gap.
Maximum diffraction occurs.
(c) In amplitude modulation the radio wave is the signal and the sound wave is the
carrier.
The radio wave is the carrier and the sound wave is the signal.
(d) Microwaves diffract more than radio waves because of their longer wavelength.
Radio waves have the longest wave and therefore diffract the most.
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OCR GCSE
Physics
Self-assessment quiz: answers
P5f Foundation and Higher
Nature of waves
1
Fill in the gaps using words from the list. Choose four different words from the list.
destructive
larger
interference
cancel
crests
constructive
[F/H]
trough
Interference occurs between waves when they overlap. When the crest of one wave arrives at
a point at the same time as a trough from another they are out of phase and cancel each other
out. This is known as destructive interference. If two crests or two troughs arrive at the same
time they are in phase, adding together to form a larger wave. This is known as constructive
interference.
2
3
True or false? Put T or F in the boxes.
[H]
Diffraction patterns are proof that light acts like a stream of particles.
F
An even number of half wavelengths leads to destructive interference.
F
Light can be polarised as it is a transverse wave.
T
Interference patterns are due to light being diffracted.
T
Complete these sentences
[H]
Unpolarised light vibrates in all directions.
After passing through a polarising filter the whole wave is contained in just one plane.
A second filter will allow light to pass through if it is lined up with the first.
The wave is blocked if the second filter is turned through 90 degrees.
When light reflects off water it is part polarised because more waves are reflected parallel
to the surface.
Polaroid lenses reduce glare because they block reflections from a horizontal surface such
as water.
13 of 15
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OCR GCSE
Physics
Self-assessment quiz: answers
P5g Foundation and Higher
Refraction and TIR
1
Solve the clues across. The shaded column is a scientific word of which a rainbow is
one.
[F/H]
2
5
I
N
C
I
D
D
7
2
1
S
P
E
E
D
I
S
P
E
R
S
I
O
N
3
R
E
F
R
A
C
T
I
O
4
C
R
I
T
I
C
A
L
N
T
6
R
E
D
O
U
N
D
A
R
Y
8
M
E
D
I
U
M
E
B
N
1
This changes when a wave reaches a boundary.
2
This effect produces a rainbow when white light goes through a prism.
3
This happens at a boundary when the incident angle is small.
4
At this angle light travels along the boundary.
5
This is the angle between the normal line and the wave going towards a boundary.
6
The colour that is refracted the least through a prism.
7
The junction between air and plastic is an example of a ___________
8
The scientific name for the stuff a wave is travelling through.
True or false? Put T or F in the boxes.
Refraction occurs at a boundary due to the change in a wave’s frequency.
When a wave’s speed decreases it bends towards the normal.
3
[F/H]
F
T
Waves refract the most when there is a small change in speed.
F
Dispersion occurs because colours have different wave speeds.
T
Fill in the gaps using words from the list. Choose four different words from the list.
higher
lower
greater
lower
[H]
higher
Total internal reflection can only occur when a ray of light travels from a medium with
a higher refractive index into a medium with a lower one. Also the angle of incidence
must be greater than the critical angle. The higher the refractive index of a medium the
lower its critical angle.
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This document may have been altered from the original.
OCR GCSE
Physics
Self-assessment quiz: answers
P5h Foundation and Higher
Lenses
1
Complete the following ray diagram and mark the focal point on the diagram.
[F/H]
focal point
2
Complete the following sentences using the words given.
convex
real
converging
focal length
smaller
[F]
centre
(a) A convex lens sometimes known as a converging lens.
(b) The distance from the centre of the lens to the focal point is known as the focal
length.
(c) A thick lens will have smaller focal length than a thin lens.
(d) Cameras and projectors both use convex lenses and produce real images.
3
Complete the following ray diagram by drawing two rays from the top of the object to
the top of the image.
[H]
F = focal
point
F
4
A convex lens produces an image 8 cm high of an object that was originally 4 cm high.
Calculate the magnification.
[H]
x2
5
How would you adjust a camera lens to produce a focused image on the film?
[F/H]
By moving the lens towards or away from the film (not the object!)
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© Harcourt Education 2006, OCR Gateway Science
This document may have been altered from the original.