Download P5 Booklet FINAL - Highfields School, Wolverhampton

HIGHFIELDS
SCHOOL
Physics Department
OCR GCSE Physics
P5 – Space for Reflection
Student Support Booklet
Equations
P5 – Key Words
Accelerate
Action (force)
Aerial
Amplifies
(in) Antiphase
Angle of incidence
Angle of refraction
Aperture
Camera
Cancellation
Centripetal force
Coherent
Concave
Condenser lens
Constructive
(interference)
Converging
Convex
Crests
Critical angle
Decelerate
Destructive
(interference)
Diffraction
Digital signal
An object accelerates if it speeds up
Applying a force on an object
A device for receiving or transmitting radio signals
Increases the size e.g. a radio signal
When two waves are “out of step” with each other;
crests coincide with troughs
The angle between the incident ray of light and the
normal at a given point
The angle between the refracted ray of light and the
normal at a given point.
The size of the hole through which light enters a camera
An optical instrument that produces a reduced image
on a piece of film (film camera) or light sensitive chip
(digital camera)
When two waves cancel to give reduced amplitude;
destructive interference
Force towards the centre of a circle essential for circular
motion
Waves having the same frequency, amplitude and
phase (or constant phase difference)
Curving inwards
Used in a projector to concentrate light on a slide
When two waves combine to give increased amplitude
Coming towards a point
Curving outwards
Peaks of a wave
The angle of incidence for which the angle of refraction
is 90°; larger angles of incidence result in total internal
reflection (TIR)
An object decelerates if it slows down
When two waves cancel out to give reduced amplitude
The spreading out of a wave when it passes through a
gap or around an edge. Maximum diffraction occurs
when the gap width is equal in size to the wavelength of
the wave.
A signal which is either “on” or “off”
Dispersion
The splitting of light into its different wavelengths
Diverging
Spreading out/moving away from a point
Electromagnetic waves A group of waves that carry different amounts of energy
– range from low frequency radio waves to high
frequency gamma rays.
Focal length
The distance from the optical centre of a lens to its focus
Focal plane
The plane that includes the focus (focal point)
Focal point
Focus (of a lens)
Focus
(of a lens or mirror) the point to which rays of light
converge or from which they diverge
Frequency
Number of vibrations per second, frequency is measured
in Hertz (Hz).
Fringes
Light and dark bands of light produced by two-slit
interference of monochromatic (single wavelength)
light
Geostationary satellite A satellite in orbit above the equator taking 24 hours for
one orbit
Global Positioning
A satellite navigation system that involves many satellites
System (GPS)
orbiting Earth
Gravitational attraction Force of attraction between two bodies due to their
mass
Gravitational field
A region in which a mass experiences a force
Gravity
An attractive force between objects (dependent on
their mass)
Interference
The formation of points of reinforcement and
cancellation when two sets of waves overlap
Inverse square law
When one variable is inversely proportional to the square
of another
Inverted
Upside down
Ionosphere
A region in the Earth’s atmosphere where ionisation
caused by incoming solar radiation affects the
transmission of radio waves; it extends from 70km to
400km above Earth.
Laser
Source of intense, narrow beam of light. “Light
Amplification by Stimulated Emission of Radiation”
Launch angle
The angle at which a projectile is thrown
Lens
A piece of transparent material, often glass, that is fatter
in the middle than the ends (convex) or thinner in the
middle than at the ends (concave)
Light sensitive chip
Surface in a digital camera that records light
electronically, producing a digital image
Line of sight
In direct line with no obstructions
Magnification
Magnitude
Microwaves
Momentum
Noise
Normal
Optical fibres
Orbit
Parabolic
(in) Phase
Pixels
Polar orbit
Polarised light
Polaroid
Principle axis
Projectile
Projector
Radiowaves
Range
Reaction force
Real (image)
Receiver
Refraction
Refractive index
Reinforcement
The ratio of the height of the image to the height of the
object
Size of something
Non-ionising waves used in satellite and mobile phone
networks, as well as microwave ovens
The product of mass and velocity of an object.
Unwanted signals
A line perpendicular to a surface
Very thin glass fibres that light travels along by total
internal reflection (TIR)
The path taken by a satellite
Shaped like a parabola
When two waves are “in step” with each other; crests
coincide and troughs coincide
Short for picture elements; stores data in the lightsensitive chip of a digital camera
A satellite orbit that passes over Earth’s North and South
poles
Light in which the oscillations are confined to one plane
only.
A material that absorbs light except that polarised in
one particular plane, producing polarised light
The axis, perpendicular to the face of a lens, that passes
through the optical centre
Any object thrown in Earth’s gravitational field
An optical instrument that produces an enlarged image
on a screen
Non-ionising waves used to broadcast radio and TV
programmes
The horizontal distance covered by an object
When an object feels a force it pushes back with an
equal reaction force in an opposite direction
An image that can be projected onto a screen; light
actually passes through it
Device which receives waves e.g. mobile phone
A change in speed, and usually direction, when light
passes from one medium to another e.g. from air to glass
or water
The ratio of the speed of light in a vacuum (or air) to the
speed of light in a medium
When two waves combine to give increased amplitude;
constructive interference
Relative speed
Re-transmits
Ripple tank
Satellite
Scalar
Shutter
Total internal reflection
(TIR)
Trajectory
Transmitter
Troughs
Vector
Virtual image
Wavelength
Weight
The speed of a moving object with respect to another
Sends out a signal again (often after amplification)
Equipment containing a water surface to observe wave
motion
A body orbiting a larger body e.g. communication
satellites orbit the Earth
A quantity having magnitude but no direction
In a camera, it opens and closes very quickly to let light
into the camera
Complete reflection of a light ray within glass when the
ray hits the glass/air boundary at an angle which is
greater than the critical angle.
The path of a projectile
Device which transmits waves e.g. mobile-phone mast
Lowest points of a wave
A quantity having magnitude and direction
Image formed on the same side of the lens as the
object; a virtual image formed by reflection can be seen
but cannot be projected onto a screen.
Distance between two wave peaks
Force on an object due to gravitational attraction
Module P5: Space for Reflection
P5a: Satellites, gravity and circular motion
Satellites have played a major part in the global communications revolution. We can call someone on the other side of the
world using a mobile phone or watch events around the world, as they happen, in the comfort of our own homes. This item
looks at what satellites are, their uses, including communications and satellite TV, and the physics behind what keeps them in
the correct orbit. Newton’s experiment illustrates how uncertainties about science ideas change over time, and the use of
models to explain phenomena.
GRADE G - D
Recall that gravity is the
universal force of attraction
between masses.
Recognise that a satellite is an
object that orbits a larger
object in space.
Describe the difference
between artificial and natural
satellites.
GRADE C
Explain why the Moon remains
in orbit around the Earth and
the Earth and other planets in
orbit around the Sun.
GRADE B – A*
Describe the variation of
gravitational force with
distance (idea of inverse
square law).
Explain the variation in speed
of a periodic comet during its
orbit around the Sun to
include:
• influence of highly elliptical
orbit
• variation in gravitational
force of attraction.
Explain how the orbital period
of a planet depends upon its
distance from the Sun.
Targets for
Improvement
Describe how the height
above the Earth’s surface
affects the orbit of an artificial
satellite.
Recall how the height of orbit
of an artificial satellite
determines its use.
Describe the orbit of a
geostationary artificial satellite:
• orbits the Earth once in 24
hours around the equator
• remains in a fixed position
above the Earth’s surface
• orbits above the Earth’s
equator.
Understand that artificial
satellites are continually
accelerating towards the Earth
due to the Earth’s gravitational
pull, but that their tangential
motion keeps them moving in
an approximately circular orbit.
Understand that circular
motion requires:
• a centripetal force
• gravity provides the
centripetal force for orbital
motion.
Recall some of the
applications of artificial
satellites to include:
• communications
• weather forecasting
• military uses
• scientific research
• GPS
• imaging the earth.
Explain why different satellite
applications require different
orbits, to include the orbit’s:
• height
• period
• trajectory (including polar
orbit).
Explain why artificial satellites in
lower orbits travel faster than
those in higher orbits.
P5a – Activities
1. Tick the correct boxes to show if each is a property of
geostationary satellites or polar orbital satellites:
Property
Geostationary
Polar
Orbital
Orbits above the equator
3 satellites can cover the whole Earth
Orbits at a height of 100 – 200km
Orbits at a height of 36000km
Strong centripetal acceleration
Orbits above the poles
Typical period of 90 mins
Orbital period of 24 hours
Weak centripetal acceleration
Used for communications, long range weather forecasts,
spying and GPS
Used for short-range weather forecasts and imaging Earth’s
surface
Passes over a different point each orbit.
Stays above the same point of the Earth
2. Describe the relationship between gravitational force and
distance:
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3. Explain how the orbital speed of a comet varies as it orbits
around the sun. Draw a diagram on the next page to support your
answer:
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Diagram
4. Explain why artificial satellites in lower orbits travel faster than
those in higher orbits:
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5. Artificial satellites orbit the Earth and send information back.
Satellites have many different uses. The choice of orbit for the
satellite depends on what the satellite is used for.
Describe how different types of satellite orbit the Earth. Give
examples of different uses of satellites and explain what type of
orbit should be used and why.
(6 marks)
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Module P5: Space for Reflection
P5b: Vectors and Equations of Motion
When analysing the motion of objects, knowing how fast they are travelling is only half the information. We also need to know
the direction that they are travelling in. Two cars travelling towards each other at high speed is entirely different from the same
cars travelling at the same speed in the same direction.
GRADE G - D
GRADE C
Recall that direction is
important when describing the
motion of an object.
Describe the difference
between scalar and vector
quantities:
• some quantities, (e.g. mass,
Understand how relative speed time), direction is not relevant
depends on the direction of
(scalar)
movement (in context of two
• some quantities, (e.g. force,
cars travelling on a straight
velocity, acceleration)
road).
direction is important (vector).
Calculate the vector sum from
vector diagrams of parallel
vectors (limited to force and
velocity in the same or
opposite directions).
GRADE B – A*
Calculate the resultant of two
vectors that are at right angles
to each other.
(Answers can be by
calculation or scale diagram).
Targets for
Improvement
Recall that:
• direction is not important
when measuring speed
• speed is a scalar quantity.
Use the equation:
Use the equations, including a
change of subject:
v = u + at
𝑣 2 = 𝑢2 + 2𝑎𝑠
to calculate v or u.
Recognise that for any journey:
• distance travelled can be
calculated using the equation:
distance = average speed × time
𝑠=
(𝑢 + 𝑣)
𝑡
2
Use the equation:
v = u + at
to calculate final speed only.
Use the equation, including a
change of subject:
𝑠=
(𝑢 + 𝑣)
𝑡
2
𝑠 = 𝑢𝑡 +
1 2
𝑎𝑡
2
P5b Activities
1. Use the equation sheet to answer the following questions:
a) A cyclist accelerates from rest to a velocity of 15 m/s in a
period of 10 s.
i) Calculate the acceleration the cyclist experiences.
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ii) Calculate the distance travelled by the cyclist in this time.
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b) A car is travelling at a velocity of 15 m/s when it experiences an
acceleration of 5 m/s2.
i) Given its final velocity is 35 m/s, calculate the time that the
vehicle is accelerating for.
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ii) The car approaches traffic and decelerates from 35 m/s to 10
m/s at an acceleration of -4 m/s2. Calculate how far the car
travels whilst decelerating.
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2. What is the difference between a scalar and a vector quantity?
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3. Circle those quantities below which are vector quantities:
Velocity
Force
Time
Acceleration
Mass
4. A small aeroplane is flying at 150 m/s due North and is suddenly
hit by a wind travelling at 40 m/s from the East. Find the size and
direction of the resultant velocity. You may want to use a diagram
to help you.
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5. What is meant by the term “relative speed”?
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Module P5: Space for Reflection
P5c: Projectile Motion
Many sports involve throwing, striking or kicking a ball. We are more than familiar with the path taken by a ball that is thrown to
us, yet to have our hands in the right position to catch it, requires our brain to analyse the situation very quickly. The shape of
the path or ‘trajectory’ together with the calculations behind this are considered here.
GRADE G - D
Recall and identify that the
path of an object projected
horizontally in the Earth’s
gravitational field is curved.
Recall that the path of a
projectile is called the
trajectory.
Recognise examples of
projectile motion in a range of
contexts.
GRADE C
Describe the trajectory of an
object projected in the Earth’s
gravitational field as parabolic.
GRADE B – A*
Understand that the resultant
velocity of a projectile is the
vector sum of the horizontal
and vertical velocities.
Recall that the horizontal and
vertical velocities of a
projectile are vectors.
Recall that for a projectile in
Earth's gravitational field,
ignoring air resistance
• there is no acceleration in
the horizontal direction
(a constant horizontal velocity)
• the acceleration due to
gravity acts in the vertical
direction (steadily increasing
vertical velocity).
Use the equations of motion (in
Item P5b) for an object
projected horizontally above
the Earth's surface where the
gravitational field is still uniform.
Targets for
Improvement
Recall that the range of a ball
struck in sport depends on the
launch angle, with an optimum
angle of 45°.
Recall that, other than air
resistance, the only force
acting on a ball during flight is
gravity.
Understand that projectiles
have a downward
acceleration and that this only
affects the vertical velocity.
Interpret data on the range of
projectiles at different launch
angles.
Explain how for an object
projected horizontally:
• the horizontal velocity is
unaffected by gravity
• therefore the horizontal
velocity is constant
• gravity causes the vertical
velocity to change.
P5c Activities
1. Define the following keywords related to Projectile Motion;
Projectile: ………………………………………………………………………
Trajectory: ……………………………………………………………………...
Parabolic: ………………………………………………………………………
Range: ………………………………………………………………………….
Horizontal: ……………………………………………………………………...
Vertical: ………………………………………………………………………...
2. Use the equation sheet to answer the following questions:
a) A stone is kicked horizontally off a cliff at a velocity of 20 m/s
into the sea.
i) Sketch the path the stone will follow onto the diagram above.
ii) Given that the cliff is 50 m high, calculate:
(a)
The time taken for the stone to fall into the sea.
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(b)
The horizontal distance travelled by the stone.
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b) A football is kicked at an angle of 25° to the horizontal at a
velocity of 25 m/s.
i) Complete the diagram above to show the path of the football.
ii) The football is launched with a vertical velocity of 35 m/s and a
horizontal velocity of 15 m/s.
(a)
Calculate the time taken for the ball to return to the
ground.
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(b)
Calculate the horizontal distance travelled during the
period of flight.
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Module P5: Space for Reflection
P5d: Action and Reaction
Coming to a sudden stop is far more painful and dangerous than stopping gently. Seatbelts and crumple zones in cars are
designed to bring people and moving objects to rest slowly and safely. People falling from a burning building are caught in a
‘Fireman’s Blanket’ for the same reasons. Even objects with a small mass can have a lot of momentum when struck hard and
given a high velocity, and even individual atoms can contribute momentum to launch a powerful rocket, if there are a large
enough number of atoms involved.
GRADE G - D
GRADE C
Describe and recognise that
every action has an equal and
opposite reaction.
Understand that when an
object collides with another
object or two bodies interact,
the two objects exert an equal
and opposite force on each
other.
Describe and recognise the
opposite reactions in a parallel
collision (i.e. velocities parallel).
Recall everyday examples of
collisions; to include sporting
examples and car collisions.
GRADE B – A*
(Newton’s third law of motion).
Describe the opposite
reactions in a number of static
situations including examples
involving gravity.
Understand that momentum is
a property that is always
conserved and use that to
explain:
Understand that equal but
opposite forces act in a
collision and use this to explain
• explosions
• recoil
• rocket propulsion.
Targets for
Improvement
the change in motion of the
objects, to include recoil.
Apply the principle of
conservation of momentum to
collisions of two objects
moving in the same direction
(including calculation of mass,
speed or momentum only) for
collisions when the colliding
objects coalesce using the
equation
m1 u1 + m2 u2 = (m1 + m2) v
Explain, using a particle model,
how a gas exerts a pressure on
the walls of its container.
Recall that in a rocket, the
force pushing the particles
backwards equals the force
pushing the rocket forwards.
Explain, using a particle model,
how a change in volume or
temperature produces a
change in pressure.
Explain, using kinetic theory,
rocket propulsion in terms of
fast moving particles colliding
with rocket walls creating a
force.
Explain pressure in terms of
• the change of momentum of
the particles striking the walls
creating a force
• the frequency of collisions.
Explain how, for large scale
rockets used to lift satellites into
the Earth’s orbit, sufficient
force is created to lift the
rocket:
• a large number of particles
of exhaust gas are needed
• the particles must be moving
at high speeds.
P5d Activities
1. Tick the correct boxes to show if each statement is true or false:
Statement
Every action has an equal and opposite reaction.
Momentum is usually conserved in reactions but not
always.
A car collision is an example of where momentum is
never conserved.
An explosion is an example of momentum being
conserved.
Momentum is determined by an object’s mass and
velocity.
Momentum is a scalar quantity.
True
False
2. Choose one of the false statements from Question 1 and explain
why it is false.
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3. Use the ideas of the conservation of momentum to explain
rocket propulsion.
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4. Use the equation sheet to answer the following questions:
a) What is the momentum of a man of mass 80 kg running on a
track at 9 m/s?
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b) A trolley with a mass of 2.5 kg is travelling at 5 m/s towards a
stationary trolley of mass 2.0 kg. After colliding, the trolleys stick
together. What is their common velocity?
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c) A horizontal force of 75 N acts on a stationary snooker ball of
mass 0.2 kg. The cue is in contact with the ball for 8 milliseconds
(0.008 seconds). Calculate the speed of the ball after impact.
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5. Draw a particle diagram for a gas in the box below. Use this to
explain what is meant by the term “pressure” and the factors that
affect it. Try to use the word “momentum” and “collisions” in your
answer.
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Module P5: Space for Reflection
P5e: Satellite Communication
Using microwave and satellite technology, you can call anyone from anywhere on the planet, or receive a TV signal via a
satellite dish. This technology has moved at a rapid pace. But how does the signal from our mobile phones get to the person
receiving the call and how do TV and radio broadcasts reach the viewer and listener? This item looks at why we use
microwaves to transmit information and the physics behind the communications industry.
GRADE G - D
Recall that different
frequencies are used for low
orbit satellites (relatively lower
frequency) and geostationary
satellites (relatively higher
frequency).
GRADE C
Describe how information can
be transmitted using
microwaves to orbiting artificial
satellites and then
retransmitted back to Earth or
to other satellites.
Explain why satellite
communication uses digital
signals.
GRADE B – A*
Explain why satellite
transmitting and receiving
dishes need very careful
alignment:
• the size of a satellite
communication dish is many
times the microwave
wavelength
• this produces little diffraction
hence a narrow beam that
does not spread out
• this means the receiving dish
and satellite dish need exact
alignment.
Targets for
Improvement
Recall that some radio waves
(e.g. long wavelength) are
reflected by part of the Earth’s
upper atmosphere.
Describe how electromagnetic
waves with different
frequencies behave in the
atmosphere:
Recall that some radio waves
(e.g. short wavelength) and
microwaves pass through the
Earth’s atmosphere.
• below 30 MHz are reflected
by the ionosphere
• above 30 GHz, rain, dust and
other atmospheric effects
reduce the strength of the
signal due to absorption and
scattering
• between 30 MHz and 30 GHz
can pass through the Earth’s
atmosphere.
Recall that radio waves have a Recall the wave patterns
very long wavelength.
produced by a plane wave
passing through different sized
Recognise that radio waves
gaps.
can ‘spread’ around large
objects.
Explain why long wave radio
waves have a very long range.
Describe a practical example
of waves spreading out from a
gap.
Describe how the amount of
diffraction depends upon the
size of the gap and the
wavelength of the wave,
including the conditions for
maximum diffraction.
P5e Activities
1. Complete the following table on the “range of frequencies” of
communication waves:
Wave Type
Range (Hz)
Low Frequency Radio
High Frequency Radio
Microwaves
WiFi
2. How are microwaves transmitted around the Earth?
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3. Which waves have the longest wavelength and how are they
transmitted?
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4. Reflection of waves can cause ghosting. Use the picture below
to explain what this means.
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5. Explain why the radio signals are stronger than the microwaves
at Jenny’s house?
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Module P5: Space for Reflection
P5f: Nature of Waves
Particles can behave like waves. At other times waves behave like particles. The nature of waves and the interaction of
particles is fundamental to our understanding of the world around us. This item looks at the most important of all wave
properties – interference. When people talk about interference they usually mean ‘noise’ in an electronic system or ‘crackle’ in
a radio receiver. In the topic of waves, interference means the effect produced when two waves meet and interact with each
other.
GRADE G - D
GRADE C
Describe interference as an
Describe the interference of
effect resulting from two waves two waves in terms of
that overlap.
reinforcement and
cancellation of the waves.
Recognise that when waves
overlap there are:
Apply understanding of
• areas where the waves add
interference to describe
together
practical examples of
• areas where the waves
interference effects using
subtract from each other.
sound waves, surface water
waves or microwaves.
Describe the effect of
interference on waves in
Recall that coherent wave
different contexts, to include:
sources are needed to
• sound
produce a stable interference
• light
pattern.
• water.
Recall that for light the
GRADE B – A*
Explain interference patterns in
terms of constructive and
destructive interference.
Explain how the number of half
wavelengths in the path
difference for two waves from
the same source relates to the
type of interference used.
Describe the properties of
coherent wave sources:
• same frequency
• in phase
• same amplitude.
Targets for
Improvement
Recall that light travels in
straight lines, to include recall
of evidence to support this
theory (e.g. shadows and
eclipses).
Recognise that under certain
circumstances light can
‘bend’.
Recall that all electromagnetic
waves are transverse.
Recall that explanations of the
nature of light have changed
over time, with some scientists
describing light as waves, and
some scientists describing light
as particles.
Describe reflection of light in
terms of a particle model.
coherent sources are
monochromatic light.
Describe diffraction of light for:
• a single slit
• double slits
and that the interference
patterns produced are
evidence for the wave nature
of light.
Explain what is meant by plane
polarised light.
Understand that all
electromagnetic waves are
transverse waves and so can
be plane polarised.
Explain why the particle theory
of light is not universally
accepted.
Explain a diffraction pattern for
light to include:
• the size of the gap must be
of the order of the wavelength
of light
• how the diffracted waves
interfere to produce the
pattern.
Explain how polarisation is used
in the application of Polaroid
filters and sunglasses including:
• light from some substances
(e.g. water) is partly plane
polarised
• what the Polaroid filter does
to this plane polarised light.
Explain how the wave theory
of light has supplanted the
particle theory, as the
evidence base has changed
over time.
P5f – Activities
1. Describe what the two diagrams below show and explain why
this happens:
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
2. Explain how the size of gap that a wave passes through and the
wavelength of the wave both affect the diffraction pattern for the
wave. Use diagrams to aid your explanation:
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
3. Give the definition of ‘Monochromatic light’:
……………………………………………………………………………………
……………………………………………………………………………………
4. Red light is passed through two very narrow slits to form a
pattern of red and black bands, as seen below
a) Why must the slits be very narrow?
……………………………………………………………………………………
……………………………………………………………………………………
b) Explain how the bright fringe labelled P is formed
……………………………………………………………………………………
……………………………………………………………………………………
c) What would you expect to see at point M, half way between P
….and Q? Explain your answer
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
5. Explain how polarisation is used in the application of polaroid
filters and sunglasses:
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
Module P5: Space for Reflection
P5g: Refraction of Waves
Drive along a road on a hot day and you may see water appear to be on the surface of the road. Even more strangely,
however, is that this puddle is not actually there when you get there. Such optical illusions are common place and involve the
passage of light as it enters and leaves different mediums. This item illustrates how phenomena can be explained by using
scientific theories, models and ideas.
GRADE G - D
GRADE C
Describe and recognise that
refraction involves a change in
direction of a wave due to the
wave passing from one
medium into another.
Explain why refraction occurs
at the boundary between two
media:
• when the wave speed
decreases the wave bends
towards the normal
Explain why a ray of light
travelling from air into glass has
an angle of incidence usually
greater than the angle of
refraction.
• when the wave speed
increases the wave bends
away from the normal.
Describe refractive index as a
measure of the amount of
bending after a boundary.
Use the equation:
GRADE B – A*
Interpret data on refractive
indices and speed of light
to predict the direction of
refraction (Snell’s law not
required).
Use the equation, including a
change of subject:
This will require the use of
standard form notation and/or
a scientific notation calculator.
Targets for
Improvement
Describe and recognise that
dispersion happens when light
is refracted.
Recall the order of the spectral
colours and relate this to the
order of the wavelengths.
Describe and recognise that
some, or all, of a light ray can
be reflected when travelling
from glass, or water, to air.
Recall the many uses of TIR,
including:
• optical fibres
• binoculars
• reflectors and cat’s eyes on
the road and road signs.
Recall that the amount of
bending increases with greater
change of wave speed and
refractive index.
Explain dispersion in terms of
spectral colours having
different wave speeds in
different media but the same
speeds in a vacuum.
Describe what happens to light
incident on a glass/air surface
when the angle of incidence is
less than, equal to or above
the critical angle.
Describe the optical path in
devices using TIR, including:
• optical fibres
• binoculars
• reflectors and cat’s eyes on
the road and road signs.
Recognise that different media
have different critical angles.
Explain dispersion in terms of
spectral colours having:
• a different speed in glass
• different refractive indices
• blue light having a greater
refractive index than red light.
Explain the conditions under
which total internal reflection
(TIR) can occur.
Explain how the refractive
index of a medium relates to its
critical angle.
P5g Refraction Activities
1. The diagram below shows a light ray entering a glass block.
(a) Add to the diagram the ray inside the glass and leaving the glass.
(b) Add the labels listed to the diagram
Glass
Air
Incident ray
Refracted ray
Angle of incidence
Normal
Angle of refraction
2. Complete the blanks in the following sentences.
(a)
Refraction occurs because the ________ of light changes depending on the
________ of the medium.
Light reaches a speed of _____________ m/s in a vacuum, and is a little ________
in air.
It moves more __________ in more __________ media.
(c)
speed of light (m/s)
material
vacuum
300,000,000
perspex
200,000,000
glass
200,000,000
diamond
120,000,000
Use the information in the table to calculate the refractive index of diamond.
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
3. The diagram shows light waves
entering water. Add a series of parallel
lines and an arrow to represent the
waves in the water.
Air
Water
Water
4. The diagram below shows a ray of white light entering a prism.
(a) Add a normal line in the correct position.
(b) Add lines to the diagram to show what happens to the ray inside the prism.
(c) Add lines on the right of the prism to show what happens when the light leaves the prism.
…………………………………………………
(d) Label the diagram with the colours of the spectrum in the correct order.
(e) Explain in the correct order, why the prism creates a spectrum (6 mk qu).
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
5. The diagram shows a ray of light entering a semi-circular glass block at the critical
angle.
(a) Add a line to the diagram to show what
happens to the ray.
(b) What is this process called ?
…………………………………………
………………………………………...
(c) Add a second ray to the diagram at a smaller
angle and show what happens to it.
(d) Explain why you think TIR happens.
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
Module P5: Space for Reflection
P5h: Optics
Projecting an image onto a screen is a large industry and involves big money; especially if it’s you they are projecting. The
cameras used to film the movies use a complex arrangement of lenses to zoom in and focus on the actors, and the images
they form are real but inverted. On a more modest theme many people would struggle with day-to-day life or be unable to
read clearly without spectacles. This item takes a look at the many uses of optical devices.
GRADE G - D
Recall and identify the shape
of a convex lens.
Recall that convex lenses are
also called converging lenses.
GRADE C
Describe the effect of a
convex lens on:
Explain the refraction by a
convex lens of:
• a diverging beam of light
• a parallel beam of light.
• a ray travelling parallel to the
principal axis before it is
incident on the lens
Describe what happens to light
incident on a convex lens
For a convex lens recall and
parallel to the axis.
recognise:
• principal axis
Describe the focal length of a
• focal length
convex lens as being
• focal point
measured from the centre of
• optical centre of lens.
the lens to focal point (focus).
Recognise and recall that ‘fat’
lenses have short focal lengths
and ‘thin’ lenses have long
focal lengths.
GRADE B – A*
• a ray travelling through the
focal point of the lens before it
is incident on the lens
• a ray incident on the centre
of the lens.
Targets for
Improvement
Recognise and recall that
convex lenses produce real
images on a screen.
Describe how a convex lens
produces a real image on film
and screen respectively.
Explain how to find the position
and size of the real image
formed by a convex lens by
drawing suitable ray diagrams.
(A suitable diagram may be
required or given).
Recall that convex lenses are
used:
• in cameras
• in projectors
• in some spectacles
• as a magnifying glass.
Describe the use of a convex
lens:
• in a camera
• in a projector
• as a magnifying glass.
Explain how the images
produced by cameras and
projectors are focussed.
Use the equation:
Describe the properties of real
and virtual images.
Use the equation, including a
change of subject:
P5h Optics
1. The diagram shows 5 glass blocks.
(a) Draw a one horizontal ray entering each block and show where each ray
goes when it leaves each block.
(b) If these blocks were joined together what type of lens would they
form? ………………………………………………………..
(c) Label on the diagram the focus and the focal length.
2. The diagram shows a jelly baby and a lens.
(a) Add rays to the diagram to show where the image will be formed.
F
(b)Label the diagram with the following words,
Principle axis
Image
Object
(c)State three properties of the image.
………………………………………………………………………………………….
(d)Use a ruler to take the correct measurement in order to calculate the
magnification of the lens.
……………………………………………………………………………………………
……………………………………………………………………………………………
3. This diagram show the jelly baby closer to a lens with a larger focal
length.
(a)Add rays to the diagram to show where this image will be formed.
FF
(b)State three properties of this image.
……………………………………………………………………………………………
(c)Use a ruler to take the correct measurement in order to calculate the
magnification of this lens.
……………………………………………………………………………………………
……………………………………………………………………………………………
(d)What device produces an image like this ?
……………………………………………………………………………………………
4. The table contains descriptions of images.
(a)Add a ‘V’ for virtual image or an ‘R’ for real image into the last column
of the table.
Description of Image
Cannot be projected on a screen
Image inside a camera
Image on a retina
Using a magnifying glass
Looking in a mirror
Using a telescope
A film at the cinema
Looking through a periscope in a
submarine
Image on a smart board
Real or virtual
These are six mark questions. You will also be assessed on the quality of
your written communication (spelling, punctuation and grammar).
Satellite Television requires Communications Satellites to be placed in orbit above the
Earth. They can be placed in either Low Polar or Geostationary Orbits. Explain:
o Which of the two options should be used for the Communications Satellite
o The key features of your chosen orbit
o Why the orbit is suited to the requirements of Satellite TV communication
The 6 mark question template
Science – write down
the key words/points you
will use:
(you can photocopy this page and use it to practice each of the questions)
Structure –
Write a brief plan of the
order you will write your
points :
1.
2.
3.
4.
5.
6.
6 marks? No
problem! Just
remember
SSS...
Now you are ready to
write your answer!
SPAG (spelling,
punctuation and
grammar).
Make sure you have
used full stops, commas,
and other punctuation
correctly.