Properties Of Waves Flashcards

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1
Q

What are the two types of waves?

A

Transverse and Longitudinal waves

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2
Q

What are transeverse waves?

A

Transverse waves are defined as:
Waves that vibrate or oscillate perpendicular to the direction of energy transfer.

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3
Q

Describe the energy transfer in relation to the wave motion for both types of waves.

A

The energy transfer is in the same direction as the wave motion.

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4
Q

What do all waves transfer?

A

They transfer energy, but not the particles of the medium.

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5
Q

What can tranverse waves travel through?

A

Transverse waves can move in a liquid or solid, but not a gas. However, transverse waves such as electromagnetic waves can move in a vacuum.

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6
Q

Describe the points on the transverse wave.

A

The highest above the rest/undisturbed/equilibrium position is called the peak, or crest.
The lowest below the rest/undisturbed/equilibrium position is called the trough.

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7
Q

What are some examples of tranverse waves?

A

Examples of transverse waves are:
Ripples on the surface of water
Vibrations in a guitar string
S-waves (a type of seismicwave = wave that results from an earthquake)
Electromagnetic waves (such as radio, light, X-rays etc)

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8
Q

What is a longitudinal wave?

A

Longitudinal waves are defined as:
Waves where the points along its length vibrate parallel to the direction of energy transfer.

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9
Q

What can longitudinal waves travel through and what can’t they travel through (and why)

A

They can move in solids, liquids and gases. However, as they require a medium to travel through they can not move in a vacuum (since there are no particles).

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10
Q

Why can’t longitudinal waves travel through a vacuum?

A

There are no particles for the longitudinal wave to travel through.

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11
Q

Describe the points in a longitudinal wave

A

Close together, called compressions
Spaced apart, called rarefactions

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12
Q

What are some examples of longitudinal waves?

A

Examples of longitudinal waves are:
Sound waves
P-waves (a type of seismic wave = results after an earthquake)
Pressure waves caused by repeated movements in a liquid or gas

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13
Q

How are longitudinal waves usually drawn and why?

A

Longitudinal waves are usually drawn as several lines to show that the wave is moving parallel to the direction of energy transfer.

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14
Q

What does drawing lines closer together represent on a longitudinal wave?

A

Drawing the lines closer together represents the compressions.

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15
Q

What does drawing lines further apart represent on a longitudinal wave?

A

Drawing the lines further apart represents the rarefactions.

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16
Q

What objects can we use to show transverse wave vibrations and longitudinal wave vibrations?

A

Wave vibrations can be shown on ropes (transverse) and springs (longitudinal).

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17
Q

A wave travels perpendicular to the vibration of the rope, what does this tell us about the wave?

A

That the wave is transverse and can move in a liquid or solid, but not a gas
except for some transverse waves such as electromagnetic waves can move in a vacuum.

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18
Q

A wave travels parallel to the vibration of the spring, what does this tell us about the wave?

A

The wave is longitudinal, has compressions and rarefractions, can move in solids, liquids and gases, but not in vacuums.

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19
Q

Simplified structure of a transverse wave VS longitudinal waves

A

Transverse: Peaks and Troughs
Longitudinal: Compressions an Rarefractions

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20
Q

Simplified vibration of a transverse wave VS longitudinal waves

A

Transverse: 90 degrees (perpendicular) to direction of energy transfer
Longitudinal: Parallel to direction of energy transfer

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21
Q

Can it travel through a vacuum: transverse wave VS longitudinal waves

A

Transverse: Only electromagnetic waves can travel in vacuum
Longitudinal: Cannot travel in a vacuum

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22
Q

What it can travel through: transverse wave VS longitudinal waves

A

Transverse: Can move in liquids and solids, but not gases
Longitudinal: Can move in gas, liquids and solids

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23
Q

Density of transverse waves VS longitudinal wave

A

Transverse wave: Constant density
Longitudinal wave: Changes in density

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24
Q

Pressure of transverse waves VS longitudinal wave

A

Transverse waves: Pressure is constant
Longitudinal waves: Changes in pressure

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25
Q

Speed of transverse waves VS longitudinal wave

A

Both transverse and longitudinal waves: Dependant on material it is travelling

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26
Q

What do waves transfer?

A

Waves transfer energy and information without transferring matter or partices of the medium.

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27
Q

What are waves?

A

Waves are described as oscillations or vibrations about a fixed point that transfer energy without transferring matter.

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28
Q

Give examples of oscillations or vibrations about a fixed point

A

Ripples cause particles of water to oscillate up and down and sound waves cause particles of air to vibrate back and forth.

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29
Q

What provides evidence that waves only transfer energy and information and not matter and how?

A

Objects floating on water provide evidence that waves only transfer energy and information and not matter, this is because the object is moving perpendicular to the direction of the wave by moving up and down but not traveling with the wave.

30
Q

What is a wave on the surface of a body of water?

A

A transverse wave

31
Q

What happens when a wave travels between two points?

A

When a wave travels between two points, no matter actually travels with it, the points on the wave just vibrate back and forth about fixed positions.

32
Q

What are the terms to include when describing wave motion?

A

Amplitude
Wavelength
Frequency
Time Period
Wavefront

33
Q

What is amplitude? (Detailed)

A

Amplitude is defined as: The distance from the undisturbed position to the peak or trough of a wave, given the symbol A and is measured in metres (m)

34
Q

What is the amplitude of a wave measured in?

A

Amplitude is measured in metres (m)

35
Q

What is the symbol for the amplitude of a wave?

A

The symbol for amplitude is A

36
Q

What is wavelength? (Detailed)

A

Wavelength is defined as
The distance from one point on the wave to the same point on the next wave, given the symbol λ (lambda) and is measured in metres (m)

37
Q

What is wavelength measured in?

A

Wavelength in measured in metres (m)

38
Q

What is the symbol for wavelength?

A

The symbol for wavelength is λ (lambda)

39
Q

Where is the distance along a wave typically placed on a wave diagram?

A

The distance along a wave is typically placed on the x-axis of a wave diagram.

40
Q

What is frequency of a wave? (Detailed)

A

Frequency is defined as:
The number of waves passing a point in a second, given the symbol f and is measured in Hertz (Hz).

41
Q

What is the symbol for the Frequency of a wave?

A

Frequency is given the symbol f

42
Q

What is the frequency of a wave measured in?

A

Frequency is measured in Hertz (Hz)

43
Q

What is the time period of a wave?

A

The time period/period of a wave is defined as: The time taken for a single wave to pass a point, given the symbol T and is measured in seconds (s)

44
Q

What is the equation for the Frequency of a wave?

A

f = 1/T

45
Q

What is the equation for the time period of a wave?

A

T= 1/f

46
Q

What is the purpose of wave fronts and what does each wavefront represent?

A

The purpose of wavefronts is to picture waves from above: each wavefront is used to represent a single wave.

47
Q

What does the arrow on a wavefront represent and what can it also be referred to as?

A

The arrow represents the direction the wave is moving and is sometimes referred to as ray

48
Q

What does the space between wavefront represent?

A

The space between each wavefront represents the wavelength.

49
Q

What does it represent when the wavefronts are close together?

A

When the wavefronts are close together, this represents a wave with a short wavelength

50
Q

What does it represent when the wavefronts are far apart?

A

When the wavefronts are far apart, this represents a wave with a long wavelength.

51
Q

What types of waves obey the wave speed equation?

A

All waves obey the wave speed equation.

52
Q

What is the wave speed equation? (Word and symbol)

A

WAVE SPEED = FREQUENCY × WAVELENGTH
v = f X λ

53
Q

What does the v represent in the wave speed equation?

A

The v in the wave speed equation represents wave speed in metres per second (m/s)

54
Q

What is wave speed measured in?

A

The wave speed in measured in metres per second (m/s)

55
Q

What does the f represent in the wave speed equation?

A

The f in the wave speed equation represents frequency in Hertz (Hz).

56
Q

What does the λ represent in the wave speed equation?

A

The λ in the wave equation represents wavelength in metres (m).

57
Q

What is the equation for frequency when given the wave speed and wavelength?

A

Wave speed / wavelength

58
Q

What is the equation for wavlength when given the wave speed and frequency?

A

Wave speed / wavelength

59
Q

What is the doppler effect?

A

The Doppler Effect is defined as:
The apparent change in wavelength and frequency of a wave emitted by a moving source.

60
Q

Give two scenarios of when the doppler effect can be observed

A

The frequency of the sound waves emitted by ambulance or police sirens goes from a high pitch to a low pitch as the vehicle whizzes past
Galaxies in outer space emit electromagnetic radiation - light waves - which appear to be redder than normal because because the stars are moving away from us

61
Q

Explain the doppler effect

A

When a stationary object emits waves, the waves spread out symmetrically. However, if the object emitting waves begins to move, the waves can get squashed together at one end of the object (wavelength decreases, frequency increases, wavefronts closer together), and stretched at the other end (wavelength increases, frequency decreases). However, the speed of waves is constant.

62
Q

What does it mean if the waves in front of the moving object are squashed together?

A

It means the wavelength decreases and the frequency of the waves increases.

63
Q

What does it mean if the waves behind of the moving object appear to be stretched out?

A

It means the wavelength increases and the frequency of the waves decreases.

64
Q

What does it mean if the wavelength increases?

A

It means the frequency of the waves decreases.

65
Q

What does it mean if the wavelength decreases?

A

It means the frequency of the waves increases.

66
Q

What does it mean if the frequency of the waves increases?

A

It means the wavelength decreases.

67
Q

What does it mean if the frequency of the waves decreases?

A

It means the wavelength increases.

68
Q

Explain how the frequency changes as the wavelength of the wave appears to decrease (and vice verse)

A

As the speed of the waves emitted stays constant, if frequency appears to increase as the wavelength of the wave appears to decrease, and vice versa

69
Q

State two differences between light waves and sound waves.

A

light waves are transverse and sound waves are longitudinal;
and light travels faster than sound;

70
Q

Which of these is another use for infrared waves?
(1)
A fluorescent lamps
B heating lamps
C satellite transmissions
D sterilising medical equipment

A

B: heating lamps

71
Q

State three properties that all waves share in common

A

All waves reflect and refract, all waves transfer energy without transferring matter and all waves have amplitude/wavelength/frequency

72
Q

Explain how the Doppler effect causes a change in the observed frequency of waves.

A
  • speed of waves constant;
  • if source moving away, wavefronts spread
    out / wavelength increases;
  • speed = frequency × wavelength;
  • higher wavelength and constant speed of
    waves gives lower frequency