6. Waves Flashcards Preview

AQA GCSE Physics (9-1) > 6. Waves > Flashcards

Flashcards in 6. Waves Deck (127):
1

What type of wave is a sound wave?

Longitudinal

2

Which type of vibrations move parallel to the direction of the wave?

Longitudinal

3

Which type of vibrations move perpendicular to the direction of the wave?

Transverse

4

Which waves can't travel through a vacuum?

Mechanical

5

Which waves can travel through a vacuum?

Electromagnetic

6

Which waves pass their vibrations through particles?

Mechanical

7

What is frequency measured in?

Hertz

8

If one wave passes per second, what is the frequency?

1 Hz

9

How do you work out frequency?

Frequency = 1 / Period

10

What is a period?

How long is takes for the wave to pass a point - messed in seconds

11

Equation for wave speed?

Wave speed = frequency x wavelength

12

Equation for frequency?

Frequency = speed / wavelength

13

Equation for wavelength?

Wavelength = speed / frequency

14

What is the symbol for wavelength?

Lambda

15

What does the angle of incidence equal?

The angle of reflection

16

When light enters a glass cube, which direction does it refract?

Towards the normal

17

What happens when light enters a denser glass block?

The speed of the wave decreases and it refracts towards the normal

18

When the incident ray leaves the glass block, which direction does it go in?

Away from the normal

19

What happens to the speed of the ray it leaves the glass block?

It speeds up and bends away from the normal

20

What is the speed of a wave through a vacuum?

300,000,000 or 3x10 to the power of 8

21

Do different electromagnetic waves carry different amount of energy?

Yes

22

What happens when a ray is absorbed instead of reflected?

It heats up

23

What happens as the energy of a wave increases?

The temperature and hazard increased

24

What happens as the wavelength decreases?

The frequency increases
The energy carried increases
The waves become more dangerous
The waves diffract less
The waves have a shorter range
The waves carry more information

25

What are the groups in the electromagnetic spectrum?

Gamma
X-ray
Ultraviolet
Visible
Infrared
Microwaves
Radio waves

26

What type of electromagnetic wave has the highest frequency and energy, and the shortest wavelength?

Gamma

27

What type of electromagnetic wave has the lowest frequency and energy, and the longest wavelength?

Radio waves

28

What are infrared waves used for?

To locate fire, detect humans and night vision

29

What type of wave is a light wave?

Transverse

30

What are radio waves used for?

Radio, TV, telecommunications

31

What are gamma waves used for?

Kills bacteria, radiotherapy, cancer treatment

32

What are microwaves used for?

Radar detection, satellite communications, cooking

33

What are in X-rays used for?

Examine damaged machinery and medical scans

34

What are visible waves used for?

Computers, TV, LED display, to see

35

What are ultraviolet waves used for?

Detect counterfeit banknotes

36

What are the hazards of infrared waves?

Overheating - burning

37

What are the hazards of radio waves?

None

38

What are the hazards of gamma waves?

Cancer mutations to tissue

39

What are the hazards of microwaves?

Damage parts of brain

40

What are the hazards of X-Ray's?

Body cells can be killed by high doses

41

What are the hazards of visible waves?

Intense beam damages eyes

42

What are the hazards of ultraviolet waves?

Sun burn, skin cancer

43

How are sounds made?

When an object vibrates and it causes the layer of air next to it to vibrate

44

Where do sounds travel fastest? Why?

Solids because the particles are closer together

45

Why is the no sound in a vacuum?

Because there are no particles to vibrate and pass on energy

46

What do you need to remember when doing f=v/lambda

MAKE SURE THAT THE WAVELENGTH IS IN METRES, THE TIME IN SECONDS AND FREQUENCY IN HZ

47

What is the range of normal human hearing?

20Hz to 20,000Hz

48

When will sound waves refract?

When air changes temperature (change in medium) - waves will travel slower in cooler air

49

Where does sound refract in the night?

Downwards, the air near the ground is cooler than the air higher up

50

What frequency are ultrasound waves?

Higher than 20,000Hz

51

When are ultrasound waves reflected?

When they reach a boundary between two different media

52

How do you determine how far away a boundary is?

How long the reflections take to reach the detector

53

What is ultrasound used for?

Medical

Industrial cleaning and no destructive testing of materials

54

Why does the ultrasound need to be a pulse?

So you can hear the echo

55

How is the time delay for an ultrasound and pulse worked out?

distance = speed x time

56

Why is gel used in ultrasound?

Because then there is more ultrasound absorbed. When there is a big difference between densities lots of it would be reflected.

57

What is the distance in ultrasound?

The way there and back

58

What is the depth in ultrasound?

Just the way there

59

Other uses of ultrasound?

The detection and removal of kidney stones

60

What makes seismic waves?

A sudden release of energy in the earths crust

61

What is used to detect movements of the earths crust?

A seismometer

62

What are the two types of seismic wave?

Primary and secondary

63

Properties of primary waves?

• longitudinal

• travels through solids and liquids

• travels faster

64

Properties of secondary waves?

• transverse

• only travel through solids

• travels slower

65

How does heat travel through space?

By infrared waves

66

What emits and absorbs thermal radiation?

All bodies

67

What is thermal (infrared) radiation?

The transfer of energy by electromagnetic waves

68

What is a thermograph?

The images taken using infrared radiation

69

What surface is the best emitter of infrared radiation?

Matte black surfaces

70

What surface is the worst emitter of infrared radiation?

Silver (shiny) surfaces

71

Best materials to emit infrared radiation? Best to worst

Matte black, shiny black, white, silver

72

Which kettle will cool down faster: black or metallic?

Black because it will emit more radiation

73

What direction does heat energy flow in?

From a hot object to a cooler one

74

What do good emitters also act as?

Good absorbers

75

What surface is the best absorber of infrared radiation?

Matte black surfaces

76

What surface is the worst absorber of infrared radiation?

Silver surfaces

77

Best materials to absorb infrared radiation? Best to worst

Matte black, shiny black, white, silver

78

Why are shiny surfaces the worst absorbers?

They reflect most of the radiation away

79

Why do solar panels have a black outer layer?

So it can absorb heat

80

Why are firefighters suits shiny?

They are the worst absorbers, the the best reflectors

81

Why is the back of a solar panel silver?

Reflect heat back onto pipes

82

Why are premature babies wrapped in silver blankets?

Its the worst emitter, so reduces the amount of heat that they lose

83

Why are radiators in car engines black?

It's the best emitter

84

What is a perfect black body?

An object that absorbs all the radiation that hits it

85

What does a perfect black body not do?

Reflect or transmit any radiation

86

What is the radiation emitted by a black body called?

Black body radiation

87

What is black body radiation?

The radiation emitted by a black body

88

If an object's temperature is higher, what will happen to the infrared radiation it's emitting?

Higher temperature -> more infrared radiation emitted in a given time

89

What happens as a filament lamp warms up?

• doesn't glow, emits infrared

• warms up glows dull red -> emitting visible spectrum

• orange-red

• yellow-white as filament gets hotter

90

What does the intensity of radiation at a certain wavelength depend on?

Temperature

91

What happens as temperature and radiation increases?

Radiation increases at every wavelength and the peak moves to a shorter wavelength (high frequency)

92

What happens to radiation as temperature increases?

If temperature increases, intensity of radiation increases at every wavelength so peak moves to a shorter wavelength

93

What does the temperature of the earth depend on?

1. The rate that light and infrared radiation are absorbed by the atmosphere/surface or are reflected back into space

2. The rate at which the earth emits radiation from its surface and atmosphere

94

Where does the sun's spectrum peak?

At visible wavelengths

95

What are the two major types of lens?

• concave

• convex

96

What can concave lenses also be known as?

Diverging lenses

97

What can convex lenses also be known as?

Converging lenses

98

When is there a principal focus?

When the light rays are parallel

99

In a convex lens, how does the thickness of the lens affect the focal length?

The thicker the lens, the shorter the focal length

100

What is the shape of a converging lens?

It is thicker at the centre than the edges

101

What is the shape of a diverging lens?

It is thinner at the centre than the edges

102

How is magnification calculated?

magnification = image height / object height

103

If the image is larger than the object what is the magnification equal to?

greater than 1

104

If the image is smaller than the object what is the magnification equal to?

less than 1

105

What can the image in a convex lens be?

• real or virtual

• magnified or diminished

• upright or inverted

106

How is the image transformed in a camera?

(convex lens)

• diminished

• inverted

• real

107

How is the image transformed in a projector?

(convex lens)

• magnified

• inverted

• real

108

How is the image transformed in a magnifying glass?

(convex lens)

• magnified

• upright

• virtual

109

What type of images do convex lenses give?

• virtual

• upright

• diminished

110

What happens in a convex lens when the object moves further away from the lens?

The image gets smaller and moves away from the lens

111

How is short-sightedness corrected?

The eyeball is elongated so needs a concave lens

112

How is long-sightedness corrected?

Convex lens

113

Why does white light spread out into colours after it passes through a glass pyramid?

The different wavelengths experiences different changes in speed as they enter and leave the glass so refract by different amounts

114

Which colours are refracted the most and the least?

• red is refracted the least

• violet is refracted the most

115

What are the primary colours of light?

Red, green, blue

116

What are the secondary colours of light?

Yellow, cyan, magenta

117

What does green and blue light create?

Cyan light

118

What does green and red light create?

Yellow light

119

What does green and red light create?

Magenta light

120

What does a filter do?

Only allows a small range of wavelengths to pass through

121

What does a red filter do?

Only allows red light through and absorbs blue and green light

122

What are opaque objects?

Those that do not transmit light

123

What does the colour that an objects appears depend on?

Which wavelengths are most strongly reflected

124

Why do objects appear white?

They reflect all of the wavelengths of visible light equally

125

Why does a red object look black through a blue filter?

A red object only reflects red light and the blue filter only transmits blue light, so only blue light shines on the red object and it is absorbed so it appears black

126

How is a light ray reflected by flat foil?

Reflected in a single direction (specular reflection)

127

How is a light ray reflected by crumpled foil?

Scattered (diffuse reflection)