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HIGHFIELDSSCHOOL
Physics Department
OCR GCSE Physics
P5 – Space for ReflectionStudent Support Booklet
Equations
P5 – Key WordsAccelerate An object accelerates if it speeds upAction (force) Applying a force on an objectAerial A device for receiving or transmitting radio signalsAmplifies Increases the size e.g. a radio signal(in) Antiphase When two waves are “out of step” with each other;
crests coincide with troughsAngle of incidence The angle between the incident ray of light and the
normal at a given pointAngle of refraction The angle between the refracted ray of light and the
normal at a given point.Aperture The size of the hole through which light enters a
cameraCamera An optical instrument that produces a reduced image
on a piece of film (film camera) or light sensitive chip (digital camera)
Cancellation When two waves cancel to give reduced amplitude; destructive interference
Centripetal force Force towards the centre of a circle essential for circular motion
Coherent Waves having the same frequency, amplitude and phase (or constant phase difference)
Concave Curving inwardsCondenser lens Used in a projector to concentrate light on a slideConstructive (interference)
When two waves combine to give increased amplitude
Converging Coming towards a pointConvex Curving outwardsCrests Peaks of a waveCritical angle The angle of incidence for which the angle of
refraction is 90°; larger angles of incidence result in total internal reflection (TIR)
Decelerate An object decelerates if it slows downDestructive (interference)
When two waves cancel out to give reduced amplitude
Diffraction 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.
Digital signal A signal which is either “on” or “off”Dispersion The splitting of light into its different wavelengths
Diverging Spreading out/moving away from a pointElectromagnetic 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 divergeFrequency 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 System (GPS)
A satellite navigation system that involves many satellites orbiting Earth
Gravitational attraction
Force of attraction between two bodies due to their mass
Gravitational field A region in which a mass experiences a forceGravity An attractive force between objects (dependent on
their mass)Interference The formation of points of reinforcement and
cancellation when two sets of waves overlapInverse square law When one variable is inversely proportional to the
square of anotherInverted Upside downIonosphere 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 thrownLens 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 obstructionsMagnification The ratio of the height of the image to the height of
the object
Magnitude Size of somethingMicrowaves Non-ionising waves used in satellite and mobile phone
networks, as well as microwave ovensMomentum The product of mass and velocity of an object.Noise Unwanted signalsNormal A line perpendicular to a surfaceOptical fibres Very thin glass fibres that light travels along by total
internal reflection (TIR)Orbit The path taken by a satelliteParabolic Shaped like a parabola(in) Phase When two waves are “in step” with each other; crests
coincide and troughs coincidePixels Short for picture elements; stores data in the light-
sensitive chip of a digital cameraPolar orbit A satellite orbit that passes over Earth’s North and
South polesPolarised light Light in which the oscillations are confined to one
plane only.Polaroid A material that absorbs light except that polarised in
one particular plane, producing polarised lightPrinciple axis The axis, perpendicular to the face of a lens, that
passes through the optical centreProjectile Any object thrown in Earth’s gravitational fieldProjector An optical instrument that produces an enlarged
image on a screenRadiowaves Non-ionising waves used to broadcast radio and TV
programmesRange The horizontal distance covered by an objectReaction force When an object feels a force it pushes back with an
equal reaction force in an opposite directionReal (image) An image that can be projected onto a screen; light
actually passes through itReceiver Device which receives waves e.g. mobile phoneRefraction A change in speed, and usually direction, when light
passes from one medium to another e.g. from air to glass or water
Refractive index The ratio of the speed of light in a vacuum (or air) to the speed of light in a medium
Reinforcement When two waves combine to give increased amplitude; constructive interference
Relative speed The speed of a moving object with respect to anotherRe-transmits Sends out a signal again (often after amplification)Ripple tank Equipment containing a water surface to observe
wave motion
Satellite A body orbiting a larger body e.g. communication satellites orbit the Earth
Scalar A quantity having magnitude but no directionShutter In a camera, it opens and closes very quickly to let
light into the cameraTotal internal reflection (TIR)
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.
Trajectory The path of a projectileTransmitter Device which transmits waves e.g. mobile-phone mastTroughs Lowest points of a waveVector A quantity having magnitude and directionVirtual image 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.
Wavelength Distance between two wave peaksWeight Force on an object due to gravitational attraction
Module P5: Space for ReflectionP5a: Satellites, gravity and circular motionSatellites 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 GRADE C GRADE B – A* Targets for Improvement
Recall that gravity is the universal force of attractionbetween masses.
Recognise that a satellite is an object that orbits a larger object in space.
Describe the difference between artificial and naturalsatellites.
Explain why the Moon remains in orbit around the Earth and the Earth and other planets in orbit around the Sun.
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.
Describe how the height above the Earth’s surfaceaffects the orbit of an artificial satellite.
Describe the orbit of a geostationary artificial satellite:• orbits the Earth once in 24 hours around the equator
Understand that artificial satellites are continuallyaccelerating towards the Earth due to the Earth’s gravitational pull, but that
Recall how the height of orbit of an artificial satellite determines its use.
• remains in a fixed position above the Earth’s surface• orbits above the Earth’s equator.
Understand that circular motion requires:• a centripetal force• gravity provides the centripetal force for orbital motion.
their tangential motion keeps them moving in an approximately circular orbit.
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 – Activities1. 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 equator3 satellites can cover the whole EarthOrbits at a height of 100 – 200kmOrbits at a height of 36000kmStrong centripetal accelerationOrbits above the polesTypical period of 90 minsOrbital period of 24 hoursWeak centripetal accelerationUsed for communications, long range weather forecasts, spying and GPSUsed for short-range weather forecasts and imaging Earth’s surfacePasses over a different point each orbit.Stays above the same point of the Earth2. 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 ReflectionP5b: Vectors and Equations of MotionWhen 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 GRADE B – A* Targets for Improvement
Recall that direction is important when describing themotion of an object.
Understand how relative speed depends on the direction of movement (in context of two cars travelling on a straight road).
Describe the difference between scalar and vectorquantities:• some quantities, (e.g. mass, time), direction is not relevant (scalar)• some quantities, (e.g. force, velocity, acceleration) 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).
Calculate the resultant of two vectors that are at right angles to each other.
(Answers can be by calculation or scale diagram).
Recall that:• direction is not important when measuring speed• speed is a scalar quantity.
Recognise that for any journey:• distance travelled can be calculated using the equation:
distance = average speed × time
s=(u+v )2
t
Use the equation:
v = u + at
to calculate final speed only.
Use the equation:
v = u + at
to calculate v or u.
Use the equation, including a change of subject:
s=(u+v )2
t
Use the equations, including a change of subject:
v2=u2+2as
s=ut+ 12a t 2
P5b Activities1. 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.………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………ii) Calculate the distance travelled by the cyclist in this time.………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………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.………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………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.………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
2. What is the difference between a scalar and a vector quantity?
……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………3. Circle those quantities below which are vector quantities:
Velocity Force Time AccelerationMass
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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Module P5: Space for ReflectionP5c: Projectile MotionMany 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 GRADE C GRADE B – A* Targets for Improvement
Recall and identify that the path of an object projectedhorizontally in the Earth’s gravitational field is curved.
Recall that the path of a projectile is called the trajectory.
Describe the trajectory of an object projected in the Earth’s gravitational field as parabolic.
Recall that the horizontal and vertical velocities of a projectile are vectors.
Understand that the resultant velocity of a projectile is the vector sum of the horizontal and vertical velocities.
Recognise examples of projectile motion in a range ofcontexts.
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.
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 Activities1. 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.……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
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 ReflectionP5d: Action and ReactionComing 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 GRADE B – A* Targets for Improvement
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.
(Newton’s third law of motion).
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.
Describe the opposite reactions in a number of staticsituations including examples involving gravity.
Understand that equal but opposite forces act in a collision and use this to
Understand that momentum is a property that is always conserved and use that toexplain:
• explosions• recoil• rocket propulsion.Apply the principle of
explain the change in motion of the objects, to include recoil.
conservation of momentum tocollisions 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.
Explain, using a particle model, how a change in volume or temperature produces a change in pressure.
Explain pressure in terms of
• the change of momentum of the particles striking the walls creating a force
• the frequency of collisions.Recall that in a rocket, the force pushing the particles backwards equals the force pushing the rocket forwards.
Explain, using kinetic theory, rocket propulsion in terms of fast moving particles colliding with rocket walls creating a force.
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 Activities1. Tick the correct boxes to show if each statement is true or false:
Statement True False
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.
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? ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………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?………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………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.………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………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 ReflectionP5e: Satellite CommunicationUsing 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 GRADE C GRADE B – A* Targets for Improvement
Recall that different frequencies are used for loworbit satellites (relatively lower frequency) and geostationary satellites (relatively higher frequency).
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.
Explain why satellite transmitting and receiving dishes need very careful alignment:
• the size of a satellite communication dish is manytimes 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.
Recall that some radio waves (e.g. long wavelength) are reflected by part of the Earth’s upper atmosphere.
Recall that some radio waves (e.g. short wavelength) and microwaves pass through the Earth’s atmosphere.
Describe how electromagnetic waves with different frequencies behave in the 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 very long wavelength.
Recognise that radio waves can ‘spread’ around largeobjects.
Describe a practical example of waves spreading out from a gap.
Recall the wave patterns produced by a plane wavepassing through different sized gaps.
Explain why long wave radio waves have a very long range.
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 Activities1. 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 ReflectionP5f: Nature of WavesParticles 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 GRADE B – A* Targets for Improvement
Describe interference as an effect resulting from two waves that overlap.
Recognise that when waves overlap there are:• areas where the waves add together• areas where the waves subtract from each other.
Describe the effect of interference on waves indifferent contexts, to include:• sound• light• water.
Describe the interference of two waves in terms of reinforcement and cancellation of the waves.
Apply understanding of interference to describepractical examples of interference effects using sound waves, surface water waves or microwaves.
Recall that coherent wave sources are needed to produce a stable interference pattern.Recall that for light the coherent sources are
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.
monochromatic light.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.
Describe diffraction of light for:• a single slit• double slitsand 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 aretransverse waves and so can be plane polarised.
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 thepattern.
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.
Recall that explanations of the nature of light have changed over time, with some scientists describing light as waves, and some scientists describing lightas particles.
Describe reflection of light in terms of a particle model.
Explain why the particle theory of light is not universally accepted.
Explain how the wave theory of light has supplanted the particle theory, as the evidence base has changed over time.
P5f – Activities1. Describe what the two diagrams below show and explain why this happens:
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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:
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3. Give the definition of ‘Monochromatic light’:
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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?……………………………………………………………………………………
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b) Explain how the bright fringe labelled P is formed……………………………………………………………………………………
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c) What would you expect to see at point M, half way between P ….and Q? Explain your answer……………………………………………………………………………………
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5. Explain how polarisation is used in the application of polaroid filters and sunglasses:
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Module P5: Space for ReflectionP5g: Refraction of WavesDrive 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 GRADE B – A* Targets for Improvement
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 a ray of light travelling from air into glass has an angle of incidence usually greater than the angle of refraction.
Explain why refraction occurs at the boundary between two media:• when the wave speed decreases the wave bendstowards the normal
• when the wave speed increases the wave bendsaway from the normal.
Describe refractive index as a measure of the amount of bending after a boundary.Use the equation:
Interpret data on refractive indices and speed of lightto predict the direction of refraction (Snell’s law notrequired).
Use the equation, including a change of subject:
This will require the use of standard form notation and/or a scientific notation calculator.
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.
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.
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.
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.
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 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 Activities1. 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
2. Complete the blanks in the following sentences.
(a)
(c)
Use the information in the table to calculate the refractive index of diamond.
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4. The diagram below shows a ray of white light entering a prism.
Glass Air
Incident ray Refracted ray
Angle of incidence
Normal Angle of
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.
Air
Water
(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.
material speed of light (m/s)vacuumperspex
glassdiamond
300,000,000200,000,000
200,000,000120,000,000
3. The diagram shows light waves entering water. Add a series of parallel lines and an arrow to represent the waves in the water.
Water
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(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).
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5. The diagram shows a ray of light entering a semi-circular glass block at the critical angle.
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(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.
(a) Add a line to the diagram to show what happens to the ray.
(b) What is this process called ?
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(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 ReflectionP5h: OpticsProjecting 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 GRADE C GRADE B – A* Targets for Improvement
Recall and identify the shape of a convex lens.Recall that convex lenses are also called converging lenses.
Describe what happens to light incident on a convex lens parallel to the axis.
Describe the focal length of a convex lens as being measured from the centre of the lens to focal point (focus).
Recognise and recall that ‘fat’ lenses have short focal lengths and ‘thin’ lenses have long focal lengths.
Describe the effect of a convex lens on:
• a diverging beam of light• a parallel beam of light.
For a convex lens recall and recognise:• principal axis• focal length• focal point• optical centre of lens.
Explain the refraction by a convex lens of:
• a ray travelling parallel to the principal axis before it is incident on the lens
• 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.
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.
(A suitable diagram may be required or given).
Explain how to find the position and size of the real image formed by a convex lens by drawing suitable ray diagrams.
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 Optics1. 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.
(b)Label the diagram with the following words,
Principle axis Image Object
(c)State three properties of the image.
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(d)Use a ruler to take the correct measurement in order to calculate the magnification of the lens.
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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.
(b)State three properties of this image.
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(c)Use a ruler to take the correct measurement in order to calculate the magnification of this lens.
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(d)What device produces an image like this ?
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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 Real or virtual
Cannot be projected on a screenImage inside a cameraImage on a retinaUsing a magnifying glassLooking in a mirrorUsing a telescopeA film at the cinemaLooking through a periscope in a submarineImage on a smart board
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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:Which of the two options should be used for the Communications Satellite
The key features of your chosen orbit
Why the orbit is suited to the requirements of Satellite TV communication
The 6 mark question template (you can photocopy this page and use it to practice each of the questions)
6 marks? No problem! Just remember SSS
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Science – write down the key words/points you will use:
Structure – Write a brief plan of the order you will write your points :1.
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SPAG (spelling, punctuation and grammar).
Make sure you have used full stops, commas, and other
Now you are ready to write your answer!
