Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

GCSE Physics > P14 - Light > Flashcards

P14 - Light Flashcards

You may prefer our related Brainscape-certified flashcards:
GCSE Geography - AQA flashcards Physics 101 flashcards GCSE Religious Studies - Edexcel Route B flashcards GCSE Religious Studies - Eduqas Route A flashcards GCSE Religious Studies - Edexcel Route A flashcards GCSE Religious Studies - Eduqas Route B flashcards AP® Physics flashcards
1
Q

How does light travel?

A

In straight lines.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What does the Law of Reflection state?

A

The angle of incidence = The angle of reflection

i° = r°

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the normal?

A

The normal is a line perpendicular to a specific point on the mirror.

(If the mirror is flat, the normal is perpendicular to every spot on the mirror).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a ‘Ray Diagram’?

A

A diagram which shows how light reflects or refracts.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How would you draw a ‘ray diagram’ of an object being seen by an observer in a mirror?

A

1) Draw the mirror.
2) Find the middle point on the mirror between the object and the observer.
3) Draw a line from the mirror to the observer. Draw a line from the mirror to the object.
4) Label the incident ray (from the apple to the mirror) and the reflected ray (from the mirror to the observer)
5) Label the angles (i°=r°)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How would you position the virtual image on a ray diagram?

A

Extend the reflected ray THROUGH the mirror. The ‘virtual’ image will be on the opposite side of the object.

(See book)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is specular reflection?

A

Reflection on a smooth surface in a single direction with no scattering of light.

CLEAR IMAGE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is diffuse reflection?

A

Reflection on a rough surface that scatters the light in different directions.

DISTORTED IMAGE - (E.g funhouse mirror)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Why does diffuse reflection distort the image?

A

The surfaces are uneven and curved.

Therefore, the normal is different for every ray of light.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is refraction?

A

The bending of light caused by the waves changing speed at a boundary.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Why does refraction happen?

A

Waves change speed as they travel across a boundary between two different materials - (with different refractive index’s)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the refractive index, n of a material?

A

How optically dense a material is.

Symbol for refractive index = n

-The higher the refractive index, the more slowly light will travel through.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the refractive index of air?

A

n = 1

This is not that dense so waves travel quite fast.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What happens when waves go from fast to slow? (E.g air to glass - slowing down)

A

Fast to Slow = towards the normal:

F—>st

The refracted ray is at a smaller angle than the incidence ray.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens when waves go from slow to fast? (E.g glass to air - speeding up)

A

Slow to fast = away from the normal:

S—>fa

The refracted ray is at a larger angle than the incidence ray.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens when light passes through a block of glass or perspex?

A

As light enters the block it slows down : ‘f—>st’ It moves towards the normal.
As light leaves the block it speeds up: ‘s—>fa’ It moves away from the normal.

  • There will be 2 different changes of direction. When light goes into the glass; when the light goes from the glass into the air.
  • The angles at each boundary’s will be different due to the refraction caused by different optical density’s.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the aim of the Refraction Required Practical?

A

Investigating the refraction of light through a perspex block, and to use this to predict the refraction of light in other substances.

(See Required Practicals)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How is the refractive index actually calculated?

A

Angle of incidence = i°
Angle of refraction = r°

refractive index = sin (i°) / sin (r°)

n = sin (i°) / sin (r°)

EXAMPLE:

If i° = 10° , and r° = 7°:

n = sin (10) / sin (7) = 1.4

n = 1.4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the colours of light?

A 
Red
Orange
Yellow
Green
Blue
Indigo
Violet

ROYGBIV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How does the wavelength vary between the colours of light? How does freqeuncy vary?

A

Red has the longest wavelength —> RL (*Robert Lewandowski)
Violet has the shortest wavelength

Red has the lowest frequency —> RL (*Robert Lewandowski)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How does the wavelength of the colours of light impact how it refracts?

A

Red refracts the least —> RL (*Robert Lewandowski)
Violet refracts the most.

Refraction is all about the speed of the wave:
V = f λ

The longer or shorter the wavelenght (λ), the faster or slower the wave will travel. This effects how it refracts.

Red light has the Longest wavelength so it will refract the Least as it slows down the least (waves already moving very quickly).
Violet light has the Shortest wavelength so it will refract the Most as it is slows down the most (waves already moving slower).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What colour is made if you mix all the colours of light?

A

White

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What occurs when you shine white light at a prism?

A

Dispersion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is dispersion?

A

The separating of light into colours of different wavelengths caused by the refraction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What colour would refract the most through a prism?

A

Violet as it has the shortest wavelength.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Why does a rainbow occur?

A

A rainbow happens when light refracts through the water (rain) causing an arch of visible colours.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What order are the colours in a rainbow (top to bottom)?

A

Same as ROYGBIV

Red, Orange, Yellow, Green, Blue, Indigo, Violet.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is a double rainbow caused by? How do the order of colours differ?

A

The original rainbow reflecting in the sky.

The order is inverted as it is a reflection:

Violet, Indigo, Blue, Green, Yellow, Orange, Red.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What does the colour of a surface/object depend on?

A

The light the surface/object absorbs and/or reflects.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Why does a white surface show all colour?

A

White reflects all colours of light on the visible spectrum (ROYGBIV)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What colour light does black reflect?

A

None.

Black absorbs all colours of light (*think of a perfect black body absobing all the infrared)

32
Q

What are the primary light colours?

A

Red, Green, Blue (RGB) - (NOT RED, Yellow, Blue)

33
Q

What colour light do red surfaces reflect and absorb?

A

Red surfaces absorb all light, but reflect red light.

34
Q

What colour light do green surfaces reflect and absorb?

A

Green surfaces absorb all light, but reflect green light.

35
Q

What colour light do blue surfaces reflect and absorb?

A

Blue surfaces absorb all light, but reflect blue light.

36
Q

What are the secondary light colours?

A

Magenta, Yellow, Cyan (turquoise)

37
Q

How is Magenta light made?

A

Mixing red light and blue light.

38
Q

How is yellow light made?

A

Mixing red light and green light.

39
Q

How is cyan (turquoise) light made?

A

Mixing green and blue light.

40
Q

What colour light do magenta surfaces reflect and absorb?

A

Magenta surfaces absorb all light, except they reflect red and blue light.

41
Q

What colour light do yellow surfaces reflect and absorb?

A

Yellow surfaces absorb all light, except they reflect red and green light.

42
Q

What colour light do cyan (turquoise) surfaces reflect and absorb?

A

Cyan (turquoise) surfaces absorb all light, except they reflect green and blue light.

43
Q

What is the rule for the secondary colours of light absorbing and reflecting light?

A

They absorb all colours, except the 2 primary colours that make it.

44
Q

What happens when you don’t shine white light (e.g just a blue light) at a surface?

A

A blue surface under a blue light appears blue.

A red surface under a blue light appears black.

45
Q

Why does a surface appear black when the light shining at the surface is not white or the colour of the surface?

A

Because the light cannot be reflected by the surface, the surface cannot reflect any light, so it appears black.

Black surfaces absorb all light.

46
Q

What is an opaque object?

A

An object that absorbs all the light that reaches it.

47
Q

What is a translucent object?

A

An object that transmits light but scatters or refracts it.

48
Q

What is a transparent object?

A

An object that transmits light without scattering or refracting it.

49
Q

What are the 2 lens shapes?

A

1) Convex

2) Concave

50
Q

What does a convex lens do?

A

A convex (converging) lens converges light (focuses it).

Treats long-sightedness (makes it fall shorter).

51
Q

What does a concave lens do?

A

A concave (diverging) lens diverges light (spreads it out and back).

Treats short-sightedness (pushes light back).

52
Q

What is the focal point?

A

The point where light is focused by a lens.

53
Q

What is the focal length?

A

The length between the focal point and the centre of the lens.

54
Q

What is the equation for magnification produced by a lens?

A

I = AM

Magnification = Image height / Actual Object height

55
Q

What diagram can be used to determine the position and nature of an image formed by a lens?

A

A ray diagram.

56
Q

What is a real image? Are real images inverted or upright?

A

A real image is an image that can be formed on a screen.

Real images are always inverted.

57
Q

What is a virtual image? Are virtual images upright or inverted?

A

A virtual image is formed when light rays from a source do not cross to form an image. Instead they can be traced back to a point behind the lens.

Virtual images are always upright.

58
Q

What is an upright image?

A

The image is the right way up.

59
Q

What is an inverted image?

A

The image is upside down.

60
Q

What is a magnified image?

A

The image is enlarged.

61
Q

What is a diminished image?

A

The image is smaller.

62
Q

What is the symbol for a convex lens?

A

A vertical arrow - to show that convex lenses are thicker at the centre and narrower at the edges.


V

63
Q

What image is formed if the object is 2 or more focal lengths away from a convex lens (2F)?

A

A real, inverted, diminished image.

64
Q

What image is formed if the object is between 1 and 2 focal lengths away from a convex lens? (1-2F)

A

A real, inverted, magnified image.

65
Q

Summary: How do you form a real, inverted image with a convex lens?

A

Position the object either:

  • greater than 2F
  • between 1 and 2F
66
Q

What image is formed when the object is less than 1 focal length away from a convex lens?

A

A virtual, upright and magnified/enlarged image.

67
Q

Summary: How do you form a virtual, upright, enlarged image with a convex lens?

A

Place the object less than 1 focal lenght away from the convex lens.

68
Q

What does a ray diagram look like for a convex lens?

A

A ray diagram has a principal (focal) axis and a convex lens:

        ^ ———|——— 2F   F   V     F    2F

There are focal points along the principal axis.

69
Q

What 3 lines should you draw on a ray diagram to determine the nature and position of an image produced by a convex lens?

A

1) Line from top of object through the origin (0,0)
2) A line parallel to the principal axis up to the lens, then down through the focal point.
3) A line from the object down through the focal point on the same side to the lens, then parallel to the axis.

70
Q

Where should the lines meet if the image is real for a convex lens?

A

The opposite side of the lens.

71
Q

What should the image height be in comparison to the object height if the points meet on the opposite side to the object?

A

It should be smaller. The object is diminished.

72
Q

Where should the lines meet if the image is virtual for a convex lens?

A

The lines won’t meet in the opposite side as they will diverge.

The lines should be ‘traced back’ and extended to meet so that the image is on the same side as the object.

73
Q

What do ray diagrams for convex lenses tell us about the side that images are formed in relation to to objects?

A

Real images are formed on the opposite side of the lens.

Virtual images are formed on the same side of the lens as they have to be ‘traced back’.

74
Q

What is the symbol for a concave lens on a ray diagram?

A

An double ended inverted arrow:

V
|

75
Q

What 3 lines must be drawn to determine the nature and position of an image formed by a concave lens?

A

1) Top of object through centre/origin (0,0).
2) Horizontal line from Top of object to lens -
3) then diagonal upwards as if it had gone through the focal point on the other side.

76
Q

What is the nature and position of any image formed by a concave lens?

A

The image is virtual, upright and diminished.

GCSE Physics (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions