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Physics GCSE OCR Gateway B > P5 - Space For Reflection > Flashcards

P5 - Space For Reflection Flashcards

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1
Q

P5 - Space for Reflection

What happens if the distance from a planet is doubled (gravity)?

A

Gravitational force decreases by a factor of 4 (22)

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2
Q

P5 - Space for Reflection

What is the formula for gravity?

A

F ∝ 1/d²

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3
Q

P5 - Space for Reflection

What does gravity provide to ensure planets orbit in a circular motion?

A

A centripetal force - it is directed to the centre of the circle.

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4
Q

P5 - Space for Reflection

What happens if a planet is twice as close (gravity)?

A

Gravitational force increases by a factor of 4

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5
Q

P5 - Space for Reflection

What is speed?

A

How fast something’s going

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6
Q

P5 - Space for Reflection

Why is velocity a more useful measure of motion?

A

Because it describes both the speed and direction

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7
Q

P5 - Space for Reflection

What is a scalar quantity?

A

A quantity like speed that has only a number

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8
Q

P5 - Space for Reflection

What are some examples of scalar quantities?

A

Speed Mass Temperature Time Length

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9
Q

P5 - Space for Reflection

What is a vector quantity?

A

A quantity like velocity that has a direction and a number

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10
Q

P5 - Space for Reflection

What are some examples of vector quantities?

A

Velocity Force Displacement Acceleration Momentum

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11
Q

P5 - Space for Reflection

What is relative speed?

A

How fast something is going relative to something else.

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12
Q

P5 - Space for Reflection

What will the relative speed be of a car going the same way as you?

A

The car will have a small speed relative to your car

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13
Q

P5 - Space for Reflection

What will the relative speed be of a car going the opposite direction to you?

A

The car will have a bigger speed relative to your car.

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14
Q

P5 - Space for Reflection

What happens to the vectors if two things are moving in the same directions?

A

The vectors are added

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15
Q

P5 - Space for Reflection

What happens to the vectors if two things are moving in the same directions?

A

Vectors are subtracted

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16
Q

P5 - Space for Reflection

What is used if an object mov against the current e.g. Across the wind?

A

Pythagoras theorem. Velocity is needed.

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17
Q

P5 - Space for Reflection

What does u stand for in the equations of motion?

A

Initial velocity

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18
Q

P5 - Space for Reflection

What does v stand for in the equations of motion?

A

Final velocity

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19
Q

P5 - Space for Reflection

What does s stand for in the equations of motion?

A

Distance (or displacement)

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20
Q

P5 - Space for Reflection

What does t stand for in the equations of motion?

A

Time

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21
Q

P5 - Space for Reflection

What does a stand for in the equations of motion?

A

Acceleration

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22
Q

P5 - Space for Reflection

What is a projectile?

A

Something that is projected, or dropped and only has Earth’s gravitational field acting on it.

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23
Q

P5 - Space for Reflection

Give some examples of projectiles…

A

Golf ball, missile, football.

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24
Q

P5 - Space for Reflection

What is a trajectory?

A

The path a projectile takes

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25
Q

P5 - Space for Reflection

What shape is a projectile trajectory?

A

Parabolic

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26
Q

P5 - Space for Reflection

What does the distance a projectile travels depend on?

A

Angle it is launched at.

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27
Q

P5 - Space for Reflection

At what angle will a projectile travel the furthest?

A

45 degrees

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28
Q

P5 - Space for Reflection

What happens to the projectile if launched at less than 45 degrees?

A

Won’t travel as far

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29
Q

P5 - Space for Reflection

What happens to the distance travelled by the projectile if launched at more than 45 degrees?

A

Projectile will take longer to hit ground and won’t travel as far

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30
Q

P5 - Space for Reflection

How is motion split up?

A

Into horizontal and vertical

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31
Q

P5 - Space for Reflection

How does gravity affect motion?

A

Acts downwards - doesn’t affect horizontal at all.

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32
Q

P5 - Space for Reflection

Why does an object launched horizontally accelerate vertically?

A

Due to gravity. Has no horizontal acceleration (velocity stays same).

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33
Q

P5 - Space for Reflection

How is the resultant velocity calculated?

A

The vector sum of the separate motions

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34
Q

P5 - Space for Reflection

What happens when an object exerts a force on another object?

A

It always experiences a force in return.

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35
Q

P5 - Space for Reflection

What is an interaction pair?

A

When an object exerts a force and experiences one in return

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36
Q

P5 - Space for Reflection

What is Newton’s Third Law of Motion?

A

If object A exerts a force in object B, then object B exerts an equal and opposite force on object A.

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37
Q

P5 - Space for Reflection

What is the equation for momentum?

A

Mass x velocity

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38
Q

P5 - Space for Reflection

What are the units for momentum?

A

Kg m/s

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39
Q

P5 - Space for Reflection

In a collision when no other forces are involved, what happens to momentum?

A

It is conserved

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40
Q

P5 - Space for Reflection

What does coalesce mean?

A

Join together (when two objects collide)

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41
Q

P5 - Space for Reflection

What does m1 stand for?

A

Mass of first object

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42
Q

P5 - Space for Reflection

What does m2 stand for?

A

Mass of second object

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43
Q

P5 - Space for Reflection

What does u1 stand for?

A

Velocity of first object

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44
Q

P5 - Space for Reflection

What does u2 stand for?

A

Velocity of second object

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45
Q

P5 - Space for Reflection

What does v stand for in the momentum equation?

A

Velocity of combined objects

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46
Q

P5 - Space for Reflection

If the forces are equal how does anything move?

A

The forces are acting on different objects

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47
Q

P5 - Space for Reflection

What does kinetic theory say that gases consist of?

A

Very small particles constantly moving in random directions.

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48
Q

P5 - Space for Reflection

How much space do the gas particles take up?

A

Hardly any - most of gas is empty space.

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49
Q

P5 - Space for Reflection

What do the particles in a gas do with each other?

A

Constantly collide and bounce off each other (or off the walls).

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50
Q

P5 - Space for Reflection

Why do gas particles exert a force when they collide?

A

Because gas particles have some mass.

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51
Q

P5 - Space for Reflection

What happens with gas particles in a sealed container?

A

Gas particles smash against container walls - creates outward pressure.

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52
Q

P5 - Space for Reflection

What happens when the same volume of gas is put in a bigger container?

A

Larger volume decreases pressure. Fewer collisions between gas particles and walls.

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53
Q

P5 - Space for Reflection

What happens when the volume is reduced in a gas container?

A

Particles are more squashed - hit walls more often - pressure increase.

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54
Q

P5 - Space for Reflection

What does the pressure of a gas depend on?

A

How fast the particles are moving and how often they hit the container walls.

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55
Q

P5 - Space for Reflection

What happens if you heat a gas?

A

Particles move faster and have more kinetic energy. Hit container wall more often, creating more pressure.

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56
Q

P5 - Space for Reflection

What happens if a gas is cooled?

A

Particles have less kinetic energy - hit walls with less force and less often - pressure reduced.

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57
Q

P5 - Space for Reflection

As well as moving and having a mass, what else do gas particles have?

A

Momentum

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58
Q

P5 - Space for Reflection

What happens to momentum when gas particles hit the container walls?

A

Changes velocity and momentum - exerts force on container (pressure).

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59
Q

P5 - Space for Reflection

What is an orbit?

A

A balance between the forward motion of an object and a force pulling it inwards. (centripetal)

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60
Q

P5 - Space for Reflection

What provides the centripetal force so the planets orbit the Sun in orbits?

A

Gravitational force between each planet and the sun.

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61
Q

P5 - Space for Reflection

There must be a force acting on it if…

A

An object is travelling in a circle and constantly changing direction.

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62
Q

P5 - Space for Reflection

Why does the moon orbit the earth?

A

Because of the centripetal force produced by the gravitational force between Earth and Moon.

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63
Q

P5 - Space for Reflection

What happens to gravity the closer you get to a star or planet?

A

Stronger force of attraction

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64
Q

P5 - Space for Reflection

What does a stronger force of attraction mean the planets do?

A

Planets nearer sun move faster and cover orbits quicker.

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65
Q

P5 - Space for Reflection

In addition to planets/stars, what else are held in orbit by gravity?

A

Moons, artificial satellites and space stations.

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66
Q

P5 - Space for Reflection

What type of orbit do periodic comets have?

A

Highly elliptical orbits

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67
Q

P5 - Space for Reflection

What happens to comets when they are closer to the sun?

A

Greater the gravitational force of attraction. Travel much faster here.

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68
Q

P5 - Space for Reflection

What type of orbit do communications satellites need?

A

Quite high orbit. Above equator. Orbit once every 24hrs.

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69
Q

P5 - Space for Reflection

Whereabouts do communications satellites stay in relation to the earth?

A

Over same point. Earth rotates with them.

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70
Q

P5 - Space for Reflection

What is the name given to communications satellites?

A

Geostationary artificial satellites/geosynchronous satellites.

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71
Q

P5 - Space for Reflection

What are geostationary satellites ideal for?

A

Telephone, TV and radio.

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72
Q

P5 - Space for Reflection

Why are geostationary satellites ideal for TV, radio and telephone?

A

Stay at same point above Earth and can transfer signals from one side of earth to another in fraction of a second.

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73
Q

P5 - Space for Reflection

Why are geostationary satellites not used for weather and spying satellites?

A

Too high and too stationary

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74
Q

P5 - Space for Reflection

What kind of orbit do weather and spying satellites need?

A

Low polar orbit, passing over both poles.

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75
Q

P5 - Space for Reflection

What happens in a low polar orbit?

A

Satellite sweeps over both poles whilst earth rotates beneath it.

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76
Q

P5 - Space for Reflection

What is the difference for low polar orbit satellites in terms of gravity?

A

Much closer to earth = pull of gravity stronger and move faster.

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77
Q

P5 - Space for Reflection

How long is the orbit of a low polar orbit satellite?

A

Often under 2 hours

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78
Q

P5 - Space for Reflection

What happens each time the low polar orbit satellite orbits and what does this allow?

A

It can scan the next bit of globe and allows whole surface. To be monitored each day.

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79
Q

P5 - Space for Reflection

What wave do communications to and from satellites use?

A

Microwaves

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80
Q

P5 - Space for Reflection

How are signals for satellite TV and phones transmitted?

A

From transmitter. Picked up by satellite receiver dish orbiting 1000s of km above Earth. Satellite transmits signal back to earth in different direction and received by satellite dish on ground. OR satellites receiving signal retransmit it to other satellites and eventually back to earth.

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81
Q

P5 - Space for Reflection

What type of frequency do microwaves have?

A

High frequency - over 3,000MHz (3GHz)

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82
Q

P5 - Space for Reflection

How can microwaves reach distant parts of the planet?

A

They pass easily through the atmosphere to satellites orbiting Earth.

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83
Q

P5 - Space for Reflection

How is the frequency different for low orbit satellites than those in a geostationary orbit?

A

Those in low orbit use lower frequencies.

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84
Q

P5 - Space for Reflection

Why do satellite signals weaken?

A

They travel over long distances (losing intensity and picking up interference).

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85
Q

P5 - Space for Reflection

Why are digital signals used for satellites?

A

High quality and don’t suffer as much interference.

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86
Q

P5 - Space for Reflection

What is the magnification formula?

A

image size ÷ object size

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87
Q

P5 - Space for Reflection

What type of lenses do magnifying glasses use to create images?

A

Convex lenses

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88
Q

P5 - Space for Reflection

Where must the object being magnified be placed?

A

Closer to the lens than the focal length

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89
Q

P5 - Space for Reflection

What image is produced from a magnifying glass?

A

Virtual image

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90
Q

P5 - Space for Reflection

What are the stages when photographing an object?

A

Light from object travels to camera and is refracted by lens, forming an image on the light sensor.

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91
Q

P5 - Space for Reflection

What is the image type when taking a photograph?

A

Real image - light rays actually meet

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92
Q

P5 - Space for Reflection

What is the image size when taking photos? Why?

A

Smaller than object because object’s further away than focal length of lens

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93
Q

P5 - Space for Reflection

How does the image appear in a photo?

A

Inverted (upside down)

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94
Q

P5 - Space for Reflection

Where is an object positioned for a projector?

A

Object much closer than focal length

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95
Q

P5 - Space for Reflection

What size if the image from a projector?

A

Larger

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96
Q

P5 - Space for Reflection

How does the object need to be placed when projecting it?

A

Upside down and very close to lens

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97
Q

P5 - Space for Reflection

What happens to light when an object is projected?

A

Refracted by lens

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98
Q

P5 - Space for Reflection

What image is produced when an object is projected?

A

Real, inverted and magnified image on screen

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99
Q

P5 - Space for Reflection

When will an image be in focus?

A

When the light that forms the image converges on the screen or sensor

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100
Q

P5 - Space for Reflection

How is the image focused in cameras/projectors?

A

By moving the lens closer to or further from the object

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101
Q

P5 - Space for Reflection

The closer the object to the lens…

A

The further from the lens the image is formed

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102
Q

P5 - Space for Reflection

If 2 speakers both play the same note at exactly the same time where does constructive interference occur?

A

When distance travelled by waves from both speakers is either same or different by a WHOLE NUMBER of wavelengths.

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103
Q

P5 - Space for Reflection

If 2 speakers both play the same note at exactly the same time, where does destructive interference occur?

A

When difference in distance travelled by waves from both speakers is 1/2 wavelength, 1 1/2 wavelength, 2 1/2 wavelength, etc.

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104
Q

P5 - Space for Reflection

What is path difference?

A

Difference in distance travelled by waves from both speakers

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105
Q

P5 - Space for Reflection

What is a pattern of loud and quiet called?

A

Interference pattern

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106
Q

P5 - Space for Reflection

What is an interference pattern?

A

Pattern of constructive (loud) and destructive (quiet) interference. Applies for all type of waves.

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107
Q

P5 - Space for Reflection

What do you need to get a stable interference pattern?

A

A coherent wave source

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108
Q

P5 - Space for Reflection

What does it mean to have a coherent wave source?

A
  1. Waves at same frequency/wavelength
  2. Waves in phase (troughs and crests line up)
  3. Waves have same amplitude
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109
Q

P5 - Space for Reflection

What is the coherent source for light?

A

Monochromatic light (type produces interference patterns)

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110
Q

P5 - Space for Reflection

Why are EM waves with different frequencies used to transmit different types of communication signals?

A

Thay behave differently in the atmosphere

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111
Q

P5 - Space for Reflection

What happens to signals below 30MHz?

A

Radiowaves reflected off ionosphere, allowing wave to travel longer distances and deal with Earth’s curvature.

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112
Q

P5 - Space for Reflection

What happens to signals between 30MHz and 30GHz?

A

Radiowaves and Microwaves pass straight through atmosphere so transmissions must be in line of sight (can’t reflect off atmosphere).

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113
Q

P5 - Space for Reflection

What happens to signals above 30GHz?

A

Rain and dust in atmosphere absorb and scatter microwaves. This reduces signal strength, so highest frequency that can be used for satellite transmission is about 30GHz.

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114
Q

P5 - Space for Reflection

If 2 speakers both play the same note at exactly the same time, depending on where you stand, what do you hear?

A

Either loud sound or almost nothing

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115
Q

P5 - Space for Reflection

If 2 speakers both play the same note at exactly the same time what is heard in areas of constructive interference?

A

Loud sound - waves in phase and amplitude doubles

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116
Q

P5 - Space for Reflection

If 2 speakers both play the same note at exactly the same time what is heard in areas of destructive interference?

A

Almost no sound - waves exactly out of phase, cancel out.

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117
Q

P5 - Space for Reflection

What happens to all waves as they pass an object or through a narrow gap?

A

They diffract

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118
Q

P5 - Space for Reflection

What is classed as a ‘narrow gap’?

A

One which is about the same size as the wavelength.

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119
Q

P5 - Space for Reflection

What achieves the maximum amount of diffraction?

A

When size of gap = wavelength of wave

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120
Q

P5 - Space for Reflection

Why are long-wave radiowaves great for broadcasting?

A

Can diffract over hills, through tunnels and over horizon.

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121
Q

P5 - Space for Reflection

How are terrestrial TV and radio signals transmitted?

A

Using radiowaves (and a dish) and are received by an aerial.

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122
Q

P5 - Space for Reflection

How is a narrow beam produced when transmitting microwaves or radiowaves?

A

Dishes are many times larger than wavelength so waves don’t diffract much - producing a narrow beam.

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123
Q

P5 - Space for Reflection

What do all waves cause in a medium?

A

Some kind of disturbance.

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124
Q

P5 - Space for Reflection

What do water waves disturb?

A

Water particles

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125
Q

P5 - Space for Reflection

What do sound waves disturb?

A

Air particles

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126
Q

P5 - Space for Reflection

What do EM waves disturb?

A

Electric and Magnetic fields

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127
Q

P5 - Space for Reflection

What is constructive interference?

A

Waves disturb in the same direction and reinforce each other.

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128
Q

P5 - Space for Reflection

What is destructive interference?

A

Waves disturb in opposite directions and cancel each other out.

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129
Q

P5 - Space for Reflection

What is the total amplitude of a wave at any point?

A

The sum of the displacements (taking into account direction) of the wave at that point.

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130
Q
A
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131
Q

P5 - Space for Reflection

When do you get interference patterns?

A

When waves of equal frequency or wavelength overlap.

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132
Q

P5 - Space for Reflection

What happens when a wavefront passes through a gap?

A

Light from each point along the gap diffracts.

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133
Q

P5 - Space for Reflection

What must a gap be so that light will diffract?

A

About the same size as the wavelength of light.

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134
Q

P5 - Space for Reflection

What does an interference pattern create?

A

A bright central fringe, with alternating dark and bright fringes on either side.

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135
Q

P5 - Space for Reflection

What 2 theories were there in the 17th Century to explain the nature of light?

A
  • Particle theory - Isaac Newton
  • Wave theory - Christiaan Huygens
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136
Q

P5 - Space for Reflection

What could the particle theory explain?

A

Reflection and refraction

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137
Q

P5 - Space for Reflection

What could the particle theory not explain?

A

Diffraction and interference

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138
Q

P5 - Space for Reflection

Why could the particle theory not explain diffraction and interference?

A

They are both unique to waves

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139
Q

P5 - Space for Reflection

What did Thomas Young’s double slit experiment show?

A

That light could diffract (through 2 narrow slits) and interfere (to form interference patterns on screen).

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140
Q

P5 - Space for Reflection

What did Thomas Young’s Double Slit experiment involve?

A

A coherent light source (e.g. laser) shone through two narrow slits.

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141
Q

P5 - Space for Reflection

What is now accepted about light?

A

It shows properties of a wave (diffraction, interference and polarisation).

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142
Q

P5 - Space for Reflection

What type of wave are EM waves?

A

Transverse - vibrations at 90º to direction of travel.

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143
Q

P5 - Space for Reflection

How can you make (imitate) a transverse wave?

A

Shake a rope up and down/side to side, or in a mixture of directions.

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144
Q

P5 - Space for Reflection

What is plane polarisation?

A

Filtering out all vibrations of waves except a particular direction.

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145
Q

P5 - Space for Reflection

What is ordinary light a mixture of?

A

Vibrations in different directions

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146
Q

P5 - Space for Reflection

What does passing light through a polarising filter do?

A

Filter only transmits vibrations in one particular direction.

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147
Q

P5 - Space for Reflection

What is plane polarised light made up of?

A

Vibrations in one direction only

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148
Q

P5 - Space for Reflection

What happens when light is reflected from some surfaces like water?

A

It is partly plane polarised

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149
Q

P5 - Space for Reflection

What do polaroid sunglasses act as?

A

Polarising filters - can filter out reflected glare from sea/snow

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150
Q

P5 - Space for Reflection

What is refraction?

A

When waves change direction as they enter a different medium

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151
Q

P5 - Space for Reflection

What causes refraction?

A

Change of speed in waves which causes change in wavelength - NO CHANGE IN FREQ

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152
Q

P5 - Space for Reflection

What happens when a wave passes the boundary between 2 substances?

A

Changes speed

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153
Q

P5 - Space for Reflection

How does the wave refract if the wave speed decreases?

A

Wave bends towards normal

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154
Q

P5 - Space for Reflection

How does the wave refract when the wave speed increases?

A

Wave bends away from the normal.

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155
Q

P5 - Space for Reflection

What does light slow down to when it enters glass?

A

2/3 normal speed in air (about 2x108m/s rather than 3 x 108m/s)

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156
Q

P5 - Space for Reflection

What is refractive index?

A

Ratio of speed of light in a vacuum to the speed of light in a medium.

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157
Q

P5 - Space for Reflection

What is the refractive index basically a measure of?

A

The amount of bending

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158
Q

P5 - Space for Reflection

The higher the refractive index…

A

The more the light bends when it enters/leaves the medium.

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159
Q

P5 - Space for Reflection

What happens when waves hit a boundary along the normal (exactly 90º)?

A

No change in direction - change in speed and wavelength

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160
Q

P5 - Space for Reflection

How is the absolute refractive index of a material defined?

A

speed of light (c) ÷ speed of light in medium (v)

161
Q

P5 - Space for Reflection

What is the refractive index of glass and why?

A

High (around 1.5) - light slows down a lot in glass

162
Q

P5 - Space for Reflection

What is the refractive index of water compared to glass?

A

Lower (around 1.33) - light slows down less in water than in glass.

163
Q

P5 - Space for Reflection

What is the refractive index of air?

A

About same as in a vacuum - 1.

164
Q

P5 - Space for Reflection

Why are different colours of light refracted by different amounts?

A

They travel at different speeds in any given medium (but same in a vacuum).

165
Q

P5 - Space for Reflection

Which colour of light slows down the least?

A

Red - refracted least and has lowest refractive index (1.514…)

166
Q

P5 - Space for Reflection

What colour of light is refracted most?

A

Blue - higher refractive index (1.523…)

167
Q

P5 - Space for Reflection

What is used to make different colours of light emerge at different angles?

A

A prism

168
Q

P5 - Space for Reflection

What can a prism do to light?

A

Make different colours of white light refract, producing a spectrum - dispersion.

169
Q

P5 - Space for Reflection

What is dispersion?

A

When a spectrum is produced to show colours of rainbow.

170
Q

P5 - Space for Reflection

When does TIR only happen?

A

When light travels from a more dense medium with a higher RI to a less dense medium with a lower RI.

E.g. Glass to water

171
Q

P5 - Space for Reflection

What is TIR?

A

When angle of incidence is greater than critical angle, ray of light won’t come out but is reflected back into medium.

172
Q

P5 - Space for Reflection

What happens when angle of incidence is less than critical angle?

A

Most light passes through into air but little bit is internally reflected.

173
Q

P5 - Space for Reflection

What happens when angle of incidence is equal to critical angle?

A

Emerging ray travels along the surface. Quite a bit internal reflection.

174
Q

P5 - Space for Reflection

What happens when angle of incidence is greater than critical angle?

A

No light comes out - all totally internally reflected

175
Q

P5 - Space for Reflection

Different media have different critical angles so the higher the refractive index of the medium….

A

The lower the critical angle will be.

176
Q

P5 - Space for Reflection

What is the critical angle for glass?

A

About 42º

177
Q

P5 - Space for Reflection

Why is a critical angle of 42 useful in glass?

A

45º can be used to get TIR e.g. optical fibres

178
Q

P5 - Space for Reflection

What can TIR be used in?

A

Optical fibres, prisms in binoculars, reflectors, road signs and cat’s eyes.

179
Q

P5 - Space for Reflection

What is a real image?

A

Where light rays from an object come together to form an image on a screen (inc. retina - eye’s screen).

180
Q

P5 - Space for Reflection

What can you do to real images?

A

Project them onto a screen

181
Q

P5 - Space for Reflection

What is a virtual image?

A

When rays diverge so light from object appears to come from a different place.

182
Q

P5 - Space for Reflection

What can’t you do with a virtual image?

A

Project it onto a screen

183
Q

P5 - Space for Reflection

What type of image is looking in a mirror?

A

Virtual - object (face) appears behind mirror.

184
Q

P5 - Space for Reflection

What is the image when you look through a magnfiying glass?

A

Virtual - appears bigger and further away than it actually is.

185
Q

P5 - Space for Reflection

What 4 things describe an image?

A
  1. How big compared to original
  2. Real or virtual
  3. Upright or inverted
  4. Where it is (in relation to lens and focal point)
186
Q

P5 - Space for Reflection

What shape is a converging lens?

A

Convex

187
Q

P5 - Space for Reflection

What does a convex lens do to light?

A

Rays converge to a focus

188
Q

P5 - Space for Reflection

What happens if the rays entering the lens are parallel to each other and to the principal axis?

A

Focuses them at a point - focal point

189
Q

P5 - Space for Reflection

What is the focal length?

A

Distance between centre of lens and focal point

190
Q

P5 - Space for Reflection

What happens to the speed of a ray travelling parallel to the principal axis?

A

Slows down upon entry and bends towards normal.

191
Q

P5 - Space for Reflection

What happens to a ray travelling parallel to the principal axis when it hits the ‘glass to air’ boundary?

A

Speeds up - bends away from normal

192
Q

P5 - Space for Reflection

When a ray is travelling parallel to the principal axis, what does the curvature of the lens mean?

A

All the rays hitting different parts of lens are bent towards some focal point to form image.

193
Q

P5 - Space for Reflection

What does a ray passing through the optical centre of the lens appear to do?

A

Pass straight through

194
Q

P5 - Space for Reflection

How does a ray passing through the optical centre of the lens exit?

A

At same angle as entry but on opposite side to principal axis, so bent same amount - opposite direction.

195
Q

P5 - Space for Reflection

Describe how a convex lens can work in the opposite way…

A

Turns diverging rays into parallel light

196
Q

P5 - Space for Reflection

What type of image can convex lenses produce?

A

Real or virtual depending on how close object is to lens

197
Q

P5 - Space for Reflection

What will an object at 2F produce?

A

Real, inverted image, same size as object and at 2F

198
Q

P5 - Space for Reflection

What will an object between F and 2F produce?

A

Real, inverted image bigger than object and beyond 2F

199
Q

P5 - Space for Reflection

What will an object nearer than F produce?

A

Virtual image, right way up, bigger than object and on same side of lens.

200
Q

P5 - Space for Reflection

Gravitational force decreases by a factor of 4 (22)

A

What happens if the distance from a planet is doubled (gravity)?

201
Q

P5 - Space for Reflection

F ∝ 1/d²

A

What is the formula for gravity?

202
Q

P5 - Space for Reflection

A centripetal force - it is directed to the centre of the circle.

A

What does gravity provide to ensure planets orbit in a circular motion?

203
Q

P5 - Space for Reflection

Gravitational force increases by a factor of 4

A

What happens if a planet is twice as close (gravity)?

204
Q

P5 - Space for Reflection

How fast something’s going

A

What is speed?

205
Q

P5 - Space for Reflection

Because it describes both the speed and direction

A

Why is velocity a more useful measure of motion?

206
Q

P5 - Space for Reflection

A quantity like speed that has only a number

A

What is a scalar quantity?

207
Q

P5 - Space for Reflection

Speed Mass Temperature Time Length

A

What are some examples of scalar quantities?

208
Q

P5 - Space for Reflection

A quantity like velocity that has a direction and a number

A

What is a vector quantity?

209
Q

P5 - Space for Reflection

Velocity Force Displacement Acceleration Momentum

A

What are some examples of vector quantities?

210
Q

P5 - Space for Reflection

How fast something is going relative to something else.

A

What is relative speed?

211
Q

P5 - Space for Reflection

The car will have a small speed relative to your car

A

What will the relative speed be of a car going the same way as you?

212
Q

P5 - Space for Reflection

The car will have a bigger speed relative to your car.

A

What will the relative speed be of a car going the opposite direction to you?

213
Q

P5 - Space for Reflection

The vectors are added

A

What happens to the vectors if two things are moving in the same directions?

214
Q

P5 - Space for Reflection

Vectors are subtracted

A

What happens to the vectors if two things are moving in the same directions?

215
Q

P5 - Space for Reflection

Pythagoras theorem. Velocity is needed.

A

What is used if an object mov against the current e.g. Across the wind?

216
Q

P5 - Space for Reflection

Initial velocity

A

What does u stand for in the equations of motion?

217
Q

P5 - Space for Reflection

Final velocity

A

What does v stand for in the equations of motion?

218
Q

P5 - Space for Reflection

Distance (or displacement)

A

What does s stand for in the equations of motion?

219
Q

P5 - Space for Reflection

Time

A

What does t stand for in the equations of motion?

220
Q

P5 - Space for Reflection

Acceleration

A

What does a stand for in the equations of motion?

221
Q

P5 - Space for Reflection

Something that is projected, or dropped and only has Earth’s gravitational field acting on it.

A

What is a projectile?

222
Q

P5 - Space for Reflection

Golf ball, missile, football.

A

Give some examples of projectiles…

223
Q

P5 - Space for Reflection

The path a projectile takes

A

What is a trajectory?

224
Q

P5 - Space for Reflection

Parabolic

A

What shape is a projectile trajectory?

225
Q

P5 - Space for Reflection

Angle it is launched at.

A

What does the distance a projectile travels depend on?

226
Q

P5 - Space for Reflection

45 degrees

A

At what angle will a projectile travel the furthest?

227
Q

P5 - Space for Reflection

Won’t travel as far

A

What happens to the projectile if launched at less than 45 degrees?

228
Q

P5 - Space for Reflection

Projectile will take longer to hit ground and won’t travel as far

A

What happens to the distance travelled by the projectile if launched at more than 45 degrees?

229
Q

P5 - Space for Reflection

Into horizontal and vertical

A

How is motion split up?

230
Q

P5 - Space for Reflection

Acts downwards - doesn’t affect horizontal at all.

A

How does gravity affect motion?

231
Q

P5 - Space for Reflection

Due to gravity. Has no horizontal acceleration (velocity stays same).

A

Why does an object launched horizontally accelerate vertically?

232
Q

P5 - Space for Reflection

The vector sum of the separate motions

A

How is the resultant velocity calculated?

233
Q

P5 - Space for Reflection

It always experiences a force in return.

A

What happens when an object exerts a force on another object?

234
Q

P5 - Space for Reflection

When an object exerts a force and experiences one in return

A

What is an interaction pair?

235
Q

P5 - Space for Reflection

If object A exerts a force in object B, then object B exerts an equal and opposite force on object A.

A

What is Newton’s Third Law of Motion?

236
Q

P5 - Space for Reflection

Mass x velocity

A

What is the equation for momentum?

237
Q

P5 - Space for Reflection

Kg m/s

A

What are the units for momentum?

238
Q

P5 - Space for Reflection

It is conserved

A

In a collision when no other forces are involved, what happens to momentum?

239
Q

P5 - Space for Reflection

Join together (when two objects collide)

A

What does coalesce mean?

240
Q

P5 - Space for Reflection

Mass of first object

A

What does m1 stand for?

241
Q

P5 - Space for Reflection

Mass of second object

A

What does m2 stand for?

242
Q

P5 - Space for Reflection

Velocity of first object

A

What does u1 stand for?

243
Q

P5 - Space for Reflection

Velocity of second object

A

What does u2 stand for?

244
Q

P5 - Space for Reflection

Velocity of combined objects

A

What does v stand for in the momentum equation?

245
Q

P5 - Space for Reflection

The forces are acting on different objects

A

If the forces are equal how does anything move?

246
Q

P5 - Space for Reflection

Very small particles constantly moving in random directions.

A

What does kinetic theory say that gases consist of?

247
Q

P5 - Space for Reflection

Hardly any - most of gas is empty space.

A

How much space do the gas particles take up?

248
Q

P5 - Space for Reflection

Constantly collide and bounce off each other (or off the walls).

A

What do the particles in a gas do with each other?

249
Q

P5 - Space for Reflection

Because gas particles have some mass.

A

Why do gas particles exert a force when they collide?

250
Q

P5 - Space for Reflection

Gas particles smash against container walls - creates outward pressure.

A

What happens with gas particles in a sealed container?

251
Q

P5 - Space for Reflection

Larger volume decreases pressure. Fewer collisions between gas particles and walls.

A

What happens when the same volume of gas is put in a bigger container?

252
Q

P5 - Space for Reflection

Particles are more squashed - hit walls more often - pressure increase.

A

What happens when the volume is reduced in a gas container?

253
Q

P5 - Space for Reflection

How fast the particles are moving and how often they hit the container walls.

A

What does the pressure of a gas depend on?

254
Q

P5 - Space for Reflection

Particles move faster and have more kinetic energy. Hit container wall more often, creating more pressure.

A

What happens if you heat a gas?

255
Q

P5 - Space for Reflection

Particles have less kinetic energy - hit walls with less force and less often - pressure reduced.

A

What happens if a gas is cooled?

256
Q

P5 - Space for Reflection

Momentum

A

As well as moving and having a mass, what else do gas particles have?

257
Q

P5 - Space for Reflection

Changes velocity and momentum - exerts force on container (pressure).

A

What happens to momentum when gas particles hit the container walls?

258
Q

P5 - Space for Reflection

A balance between the forward motion of an object and a force pulling it inwards. (centripetal)

A

What is an orbit?

259
Q

P5 - Space for Reflection

Gravitational force between each planet and the sun.

A

What provides the centripetal force so the planets orbit the Sun in orbits?

260
Q

P5 - Space for Reflection

An object is travelling in a circle and constantly changing direction.

A

There must be a force acting on it if…

261
Q

P5 - Space for Reflection

Because of the centripetal force produced by the gravitational force between Earth and Moon.

A

Why does the moon orbit the earth?

262
Q

P5 - Space for Reflection

Stronger force of attraction

A

What happens to gravity the closer you get to a star or planet?

263
Q

P5 - Space for Reflection

Planets nearer sun move faster and cover orbits quicker.

A

What does a stronger force of attraction mean the planets do?

264
Q

P5 - Space for Reflection

Moons, artificial satellites and space stations.

A

In addition to planets/stars, what else are held in orbit by gravity?

265
Q

P5 - Space for Reflection

Highly elliptical orbits

A

What type of orbit do periodic comets have?

266
Q

P5 - Space for Reflection

Greater the gravitational force of attraction. Travel much faster here.

A

What happens to comets when they are closer to the sun?

267
Q

P5 - Space for Reflection

Quite high orbit. Above equator. Orbit once every 24hrs.

A

What type of orbit do communications satellites need?

268
Q

P5 - Space for Reflection

Over same point. Earth rotates with them.

A

Whereabouts do communications satellites stay in relation to the earth?

269
Q

P5 - Space for Reflection

Geostationary artificial satellites/geosynchronous satellites.

A

What is the name given to communications satellites?

270
Q

P5 - Space for Reflection

Telephone, TV and radio.

A

What are geostationary satellites ideal for?

271
Q

P5 - Space for Reflection

Stay at same point above Earth and can transfer signals from one side of earth to another in fraction of a second.

A

Why are geostationary satellites ideal for TV, radio and telephone?

272
Q

P5 - Space for Reflection

Too high and too stationary

A

Why are geostationary satellites not used for weather and spying satellites?

273
Q

P5 - Space for Reflection

Low polar orbit, passing over both poles.

A

What kind of orbit do weather and spying satellites need?

274
Q

P5 - Space for Reflection

Satellite sweeps over both poles whilst earth rotates beneath it.

A

What happens in a low polar orbit?

275
Q

P5 - Space for Reflection

Much closer to earth = pull of gravity stronger and move faster.

A

What is the difference for low polar orbit satellites in terms of gravity?

276
Q

P5 - Space for Reflection

Often under 2 hours

A

How long is the orbit of a low polar orbit satellite?

277
Q

P5 - Space for Reflection

It can scan the next bit of globe and allows whole surface. To be monitored each day.

A

What happens each time the low polar orbit satellite orbits and what does this allow?

278
Q

P5 - Space for Reflection

Microwaves

A

What wave do communications to and from satellites use?

279
Q

P5 - Space for Reflection

From transmitter. Picked up by satellite receiver dish orbiting 1000s of km above Earth. Satellite transmits signal back to earth in different direction and received by satellite dish on ground. OR satellites receiving signal retransmit it to other satellites and eventually back to earth.

A

How are signals for satellite TV and phones transmitted?

280
Q

P5 - Space for Reflection

High frequency - over 3,000MHz (3GHz)

A

What type of frequency do microwaves have?

281
Q

P5 - Space for Reflection

They pass easily through the atmosphere to satellites orbiting Earth.

A

How can microwaves reach distant parts of the planet?

282
Q

P5 - Space for Reflection

Those in low orbit use lower frequencies.

A

How is the frequency different for low orbit satellites than those in a geostationary orbit?

283
Q

P5 - Space for Reflection

They travel over long distances (losing intensity and picking up interference).

A

Why do satellite signals weaken?

284
Q

P5 - Space for Reflection

High quality and don’t suffer as much interference.

A

Why are digital signals used for satellites?

285
Q

P5 - Space for Reflection

image size ÷ object size

A

What is the magnification formula?

286
Q

P5 - Space for Reflection

Convex lenses

A

What type of lenses do magnifying glasses use to create images?

287
Q

P5 - Space for Reflection

Closer to the lens than the focal length

A

Where must the object being magnified be placed?

288
Q

P5 - Space for Reflection

Virtual image

A

What image is produced from a magnifying glass?

289
Q

P5 - Space for Reflection

Light from object travels to camera and is refracted by lens, forming an image on the light sensor.

A

What are the stages when photographing an object?

290
Q

P5 - Space for Reflection

Real image - light rays actually meet

A

What is the image type when taking a photograph?

291
Q

P5 - Space for Reflection

Smaller than object because object’s further away than focal length of lens

A

What is the image size when taking photos? Why?

292
Q

P5 - Space for Reflection

Inverted (upside down)

A

How does the image appear in a photo?

293
Q

P5 - Space for Reflection

Object much closer than focal length

A

Where is an object positioned for a projector?

294
Q

P5 - Space for Reflection

Larger

A

What size if the image from a projector?

295
Q

P5 - Space for Reflection

Upside down and very close to lens

A

How does the object need to be placed when projecting it?

296
Q

P5 - Space for Reflection

Refracted by lens

A

What happens to light when an object is projected?

297
Q

P5 - Space for Reflection

Real, inverted and magnified image on screen

A

What image is produced when an object is projected?

298
Q

P5 - Space for Reflection

When the light that forms the image converges on the screen or sensor

A

When will an image be in focus?

299
Q

P5 - Space for Reflection

By moving the lens closer to or further from the object

A

How is the image focused in cameras/projectors?

300
Q

P5 - Space for Reflection

The further from the lens the image is formed

A

The closer the object to the lens…

301
Q

P5 - Space for Reflection

When distance travelled by waves from both speakers is either same or different by a WHOLE NUMBER of wavelengths.

A

If 2 speakers both play the same note at exactly the same time where does constructive interference occur?

302
Q

P5 - Space for Reflection

When difference in distance travelled by waves from both speakers is 1/2 wavelength, 1 1/2 wavelength, 2 1/2 wavelength, etc.

A

If 2 speakers both play the same note at exactly the same time, where does destructive interference occur?

303
Q

P5 - Space for Reflection

Difference in distance travelled by waves from both speakers

A

What is path difference?

304
Q

P5 - Space for Reflection

Interference pattern

A

What is a pattern of loud and quiet called?

305
Q

P5 - Space for Reflection

Pattern of constructive (loud) and destructive (quiet) interference. Applies for all type of waves.

A

What is an interference pattern?

306
Q

P5 - Space for Reflection

A coherent wave source

A

What do you need to get a stable interference pattern?

307
Q

P5 - Space for Reflection

  1. Waves at same frequency/wavelength
  2. Waves in phase (troughs and crests line up)
  3. Waves have same amplitude
A

What does it mean to have a coherent wave source?

308
Q

P5 - Space for Reflection

Monochromatic light (type produces interference patterns)

A

What is the coherent source for light?

309
Q

P5 - Space for Reflection

Thay behave differently in the atmosphere

A

Why are EM waves with different frequencies used to transmit different types of communication signals?

310
Q

P5 - Space for Reflection

Radiowaves reflected off ionosphere, allowing wave to travel longer distances and deal with Earth’s curvature.

A

What happens to signals below 30MHz?

311
Q

P5 - Space for Reflection

Radiowaves and Microwaves pass straight through atmosphere so transmissions must be in line of sight (can’t reflect off atmosphere).

A

What happens to signals between 30MHz and 30GHz?

312
Q

P5 - Space for Reflection

Rain and dust in atmosphere absorb and scatter microwaves. This reduces signal strength, so highest frequency that can be used for satellite transmission is about 30GHz.

A

What happens to signals above 30GHz?

313
Q

P5 - Space for Reflection

Either loud sound or almost nothing

A

If 2 speakers both play the same note at exactly the same time, depending on where you stand, what do you hear?

314
Q

P5 - Space for Reflection

Loud sound - waves in phase and amplitude doubles

A

If 2 speakers both play the same note at exactly the same time what is heard in areas of constructive interference?

315
Q

P5 - Space for Reflection

Almost no sound - waves exactly out of phase, cancel out.

A

If 2 speakers both play the same note at exactly the same time what is heard in areas of destructive interference?

316
Q

P5 - Space for Reflection

They diffract

A

What happens to all waves as they pass an object or through a narrow gap?

317
Q

P5 - Space for Reflection

One which is about the same size as the wavelength.

A

What is classed as a ‘narrow gap’?

318
Q

P5 - Space for Reflection

When size of gap = wavelength of wave

A

What achieves the maximum amount of diffraction?

319
Q

P5 - Space for Reflection

Can diffract over hills, through tunnels and over horizon.

A

Why are long-wave radiowaves great for broadcasting?

320
Q

P5 - Space for Reflection

Using radiowaves (and a dish) and are received by an aerial.

A

How are terrestrial TV and radio signals transmitted?

321
Q

P5 - Space for Reflection

Dishes are many times larger than wavelength so waves don’t diffract much - producing a narrow beam.

A

How is a narrow beam produced when transmitting microwaves or radiowaves?

322
Q

P5 - Space for Reflection

Some kind of disturbance.

A

What do all waves cause in a medium?

323
Q

P5 - Space for Reflection

Water particles

A

What do water waves disturb?

324
Q

P5 - Space for Reflection

Air particles

A

What do sound waves disturb?

325
Q

P5 - Space for Reflection

Electric and Magnetic fields

A

What do EM waves disturb?

326
Q

P5 - Space for Reflection

Waves disturb in the same direction and reinforce each other.

A

What is constructive interference?

327
Q

P5 - Space for Reflection

Waves disturb in opposite directions and cancel each other out.

A

What is destructive interference?

328
Q

P5 - Space for Reflection

The sum of the displacements (taking into account direction) of the wave at that point.

A

What is the total amplitude of a wave at any point?

329
Q
A
330
Q

P5 - Space for Reflection

When waves of equal frequency or wavelength overlap.

A

When do you get interference patterns?

331
Q

P5 - Space for Reflection

Light from each point along the gap diffracts.

A

What happens when a wavefront passes through a gap?

332
Q

P5 - Space for Reflection

About the same size as the wavelength of light.

A

What must a gap be so that light will diffract?

333
Q

P5 - Space for Reflection

A bright central fringe, with alternating dark and bright fringes on either side.

A

What does an interference pattern create?

334
Q

P5 - Space for Reflection

  • Particle theory - Isaac Newton
  • Wave theory - Christiaan Huygens
A

What 2 theories were there in the 17th Century to explain the nature of light?

335
Q

P5 - Space for Reflection

Reflection and refraction

A

What could the particle theory explain?

336
Q

P5 - Space for Reflection

Diffraction and interference

A

What could the particle theory not explain?

337
Q

P5 - Space for Reflection

They are both unique to waves

A

Why could the particle theory not explain diffraction and interference?

338
Q

P5 - Space for Reflection

That light could diffract (through 2 narrow slits) and interfere (to form interference patterns on screen).

A

What did Thomas Young’s double slit experiment show?

339
Q

P5 - Space for Reflection

A coherent light source (e.g. laser) shone through two narrow slits.

A

What did Thomas Young’s Double Slit experiment involve?

340
Q

P5 - Space for Reflection

It shows properties of a wave (diffraction, interference and polarisation).

A

What is now accepted about light?

341
Q

P5 - Space for Reflection

Transverse - vibrations at 90º to direction of travel.

A

What type of wave are EM waves?

342
Q

P5 - Space for Reflection

Shake a rope up and down/side to side, or in a mixture of directions.

A

How can you make (imitate) a transverse wave?

343
Q

P5 - Space for Reflection

Filtering out all vibrations of waves except a particular direction.

A

What is plane polarisation?

344
Q

P5 - Space for Reflection

Vibrations in different directions

A

What is ordinary light a mixture of?

345
Q

P5 - Space for Reflection

Filter only transmits vibrations in one particular direction.

A

What does passing light through a polarising filter do?

346
Q

P5 - Space for Reflection

Vibrations in one direction only

A

What is plane polarised light made up of?

347
Q

P5 - Space for Reflection

It is partly plane polarised

A

What happens when light is reflected from some surfaces like water?

348
Q

P5 - Space for Reflection

Polarising filters - can filter out reflected glare from sea/snow

A

What do polaroid sunglasses act as?

349
Q

P5 - Space for Reflection

When waves change direction as they enter a different medium

A

What is refraction?

350
Q

P5 - Space for Reflection

Change of speed in waves which causes change in wavelength - NO CHANGE IN FREQ

A

What causes refraction?

351
Q

P5 - Space for Reflection

Changes speed

A

What happens when a wave passes the boundary between 2 substances?

352
Q

P5 - Space for Reflection

Wave bends towards normal

A

How does the wave refract if the wave speed decreases?

353
Q

P5 - Space for Reflection

Wave bends away from the normal.

A

How does the wave refract when the wave speed increases?

354
Q

P5 - Space for Reflection

2/3 normal speed in air (about 2x108m/s rather than 3 x 108m/s)

A

What does light slow down to when it enters glass?

355
Q

P5 - Space for Reflection

Ratio of speed of light in a vacuum to the speed of light in a medium.

A

What is refractive index?

356
Q

P5 - Space for Reflection

The amount of bending

A

What is the refractive index basically a measure of?

357
Q

P5 - Space for Reflection

The more the light bends when it enters/leaves the medium.

A

The higher the refractive index…

358
Q

P5 - Space for Reflection

No change in direction - change in speed and wavelength

A

What happens when waves hit a boundary along the normal (exactly 90º)?

359
Q

P5 - Space for Reflection

speed of light (c) ÷ speed of light in medium (v)

A

How is the absolute refractive index of a material defined?

360
Q

P5 - Space for Reflection

High (around 1.5) - light slows down a lot in glass

A

What is the refractive index of glass and why?

361
Q

P5 - Space for Reflection

Lower (around 1.33) - light slows down less in water than in glass.

A

What is the refractive index of water compared to glass?

362
Q

P5 - Space for Reflection

About same as in a vacuum - 1.

A

What is the refractive index of air?

363
Q

P5 - Space for Reflection

They travel at different speeds in any given medium (but same in a vacuum).

A

Why are different colours of light refracted by different amounts?

364
Q

P5 - Space for Reflection

Red - refracted least and has lowest refractive index (1.514…)

A

Which colour of light slows down the least?

365
Q

P5 - Space for Reflection

Blue - higher refractive index (1.523…)

A

What colour of light is refracted most?

366
Q

P5 - Space for Reflection

A prism

A

What is used to make different colours of light emerge at different angles?

367
Q

P5 - Space for Reflection

Make different colours of white light refract, producing a spectrum - dispersion.

A

What can a prism do to light?

368
Q

P5 - Space for Reflection

When a spectrum is produced to show colours of rainbow.

A

What is dispersion?

369
Q

P5 - Space for Reflection

When light travels from a more dense medium with a higher RI to a less dense medium with a lower RI.

E.g. Glass to water

A

When does TIR only happen?

370
Q

P5 - Space for Reflection

When angle of incidence is greater than critical angle, ray of light won’t come out but is reflected back into medium.

A

What is TIR?

371
Q

P5 - Space for Reflection

Most light passes through into air but little bit is internally reflected.

A

What happens when angle of incidence is less than critical angle?

372
Q

P5 - Space for Reflection

Emerging ray travels along the surface. Quite a bit internal reflection.

A

What happens when angle of incidence is equal to critical angle?

373
Q

P5 - Space for Reflection

No light comes out - all totally internally reflected

A

What happens when angle of incidence is greater than critical angle?

374
Q

P5 - Space for Reflection

The lower the critical angle will be.

A

Different media have different critical angles so the higher the refractive index of the medium….

375
Q

P5 - Space for Reflection

About 42º

A

What is the critical angle for glass?

376
Q

P5 - Space for Reflection

45º can be used to get TIR e.g. optical fibres

A

Why is a critical angle of 42 useful in glass?

377
Q

P5 - Space for Reflection

Optical fibres, prisms in binoculars, reflectors, road signs and cat’s eyes.

A

What can TIR be used in?

378
Q

P5 - Space for Reflection

Where light rays from an object come together to form an image on a screen (inc. retina - eye’s screen).

A

What is a real image?

379
Q

P5 - Space for Reflection

Project them onto a screen

A

What can you do to real images?

380
Q

P5 - Space for Reflection

When rays diverge so light from object appears to come from a different place.

A

What is a virtual image?

381
Q

P5 - Space for Reflection

Project it onto a screen

A

What can’t you do with a virtual image?

382
Q

P5 - Space for Reflection

Virtual - object (face) appears behind mirror.

A

What type of image is looking in a mirror?

383
Q

P5 - Space for Reflection

Virtual - appears bigger and further away than it actually is.

A

What is the image when you look through a magnfiying glass?

384
Q

P5 - Space for Reflection

  1. How big compared to original
  2. Real or virtual
  3. Upright or inverted
  4. Where it is (in relation to lens and focal point)
A

What 4 things describe an image?

385
Q

P5 - Space for Reflection

Convex

A

What shape is a converging lens?

386
Q

P5 - Space for Reflection

Rays converge to a focus

A

What does a convex lens do to light?

387
Q

P5 - Space for Reflection

Focuses them at a point - focal point

A

What happens if the rays entering the lens are parallel to each other and to the principal axis?

388
Q

P5 - Space for Reflection

Distance between centre of lens and focal point

A

What is the focal length?

389
Q

P5 - Space for Reflection

Slows down upon entry and bends towards normal.

A

What happens to the speed of a ray travelling parallel to the principal axis?

390
Q

P5 - Space for Reflection

Speeds up - bends away from normal

A

What happens to a ray travelling parallel to the principal axis when it hits the ‘glass to air’ boundary?

391
Q

P5 - Space for Reflection

All the rays hitting different parts of lens are bent towards some focal point to form image.

A

When a ray is travelling parallel to the principal axis, what does the curvature of the lens mean?

392
Q

P5 - Space for Reflection

Pass straight through

A

What does a ray passing through the optical centre of the lens appear to do?

393
Q

P5 - Space for Reflection

At same angle as entry but on opposite side to principal axis, so bent same amount - opposite direction.

A

How does a ray passing through the optical centre of the lens exit?

394
Q

P5 - Space for Reflection

Turns diverging rays into parallel light

A

Describe how a convex lens can work in the opposite way…

395
Q

P5 - Space for Reflection

Real or virtual depending on how close object is to lens

A

What type of image can convex lenses produce?

396
Q

P5 - Space for Reflection

Real, inverted image, same size as object and at 2F

A

What will an object at 2F produce?

397
Q

P5 - Space for Reflection

Real, inverted image bigger than object and beyond 2F

A

What will an object between F and 2F produce?

398
Q

P5 - Space for Reflection

Virtual image, right way up, bigger than object and on same side of lens.

A

What will an object nearer than F produce?

Physics GCSE OCR Gateway B (7 decks)

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