Waves Flashcards

1
Q

How can waves be described?

A

Waves can be described as
oscillations
, or
vibrations
, about a rest position

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2
Q

What is an oscillation?

A

Vibration

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3
Q

What do sound waves do to particles?

A

sound waves cause air particles to vibrate back and forth

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4
Q

What do ripples in the water do to particles?

A

ripples cause water particles to vibrate up and down

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5
Q

Does the direction of oscillations vary?why?

A

The direction of these oscillations is the difference between longitudinal or transverse waves.

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6
Q

Describe the oscillations in longitudinal waves…

A

In
longitudinal waves
, the vibrations are parallel to the direction of wave travel

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7
Q

What are longitudinal waves?

A

A wave that moves in the same direction as the direction in which the particles are vibrating.

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8
Q

Describe oscillations in transverse waves….

A

In
tranverse waves
, the vibrations are at right angles to the direction of wave travel.

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9
Q

What is a transverse wave?

A

A wave that moves in a direction at right angles to the way in which the particles are vibrating.

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10
Q

What do mechanical waves do to to oscillations?

A

They cause oscillations of particles in a solid, liquid or gas and must have a medium
to travel through. Once the wave has passed, the medium ends up back in its rest position.

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11
Q

What is a medium?

A

A material through which a wave can be transmitted (propagate).

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12
Q

Are mechanical waves transverse or longitudinal?

A

Mechanical waves can be longitudinal or transverse.

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13
Q

Describe the oscillations in electromagnetic waves…..

A

Electromagnetic waves cause oscillations in electrical and magnetic fields. All electromagnetic waves are transverse

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14
Q

What do all waves transfer?

A

All waves transfer energy but they do not transfer
matter
.

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15
Q

What is matter?

A

Sub-atomic particles and anything made from them, such as atoms and molecules, are matter. Energy and forces are not matter.

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16
Q

What are the key parts of a wave?

A

Rest position
Displacement
Park
Trough
Amplitude
Wavelength
Time period
Frequency

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17
Q

What is the rest position of a wave?

A

the undisturbed position of particles or fields when they are not vibrating.

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18
Q

What is the displacement of a wave?

A

the distance that a certain point in the medium has moved from its rest position.

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19
Q

What is the peak of a wave?

A

the highest point above the rest position

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20
Q

What is the trough of a wave?

A

the lowest point below the rest position

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21
Q

What is the amplitude of a wave?

A

the maximum displacement of a point of a wave from its rest position.

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22
Q

What is the wavelength of a wave?

A

distance covered by a full cycle of the wave. Usually measured from peak to peak, or trough to trough

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23
Q

What is the time period of a wave?

A

the time taken for a full cycle of the wave. Usually measured from peak to peak, or trough to trough

24
Q

What is the frequency of a wave?

A

the number of waves passing a point each second.

25
Q

Describe the vibrations in a longitudinal wave….

A

In
longitudinal waves
, the vibrations are parallel to the direction of wave travel.

26
Q

Name 3 examples of a longitudinal wave…

A

sound waves
ultrasound waves
seismic P-waves

27
Q

What do longitudinal wave show areas of?

A

Longitudinal waves show areas of
compression
and
rarefaction
:

28
Q

What is a compression?

A

An area of increased pressure. In longitudinal waves, the particles in areas of compression are closer together than on average.

29
Q

What is rarefaction?

A

An area of reduced pressure. In longitudinal waves, the particles in areas of rarefaction are further apart than on average.

30
Q

Describe the vibrations in transverse waves….

A

In
tranverse waves
, the vibrations are at right angles to the direction of wave travel.

31
Q

What is a transverse wave?

A

A wave that moves in a direction at right angles to the way in which the particles are vibrating.

32
Q

Name 5 examples of a transverse wave….

A

ripples on the surface of water
vibrations in a guitar string
a Mexican wave in a sports stadium
electromagnetic waves – eg light waves, microwaves, radio waves
seismic S-waves

33
Q

How are transverse waves often demonstrated?

A

Transverse waves are often demonstrated by moving a rope rapidly up and down.

34
Q

What is air made from?

A

Many tiny particles

35
Q

What happens to the tiny particles in air when sound is created?

A

The air particles vibrate and collide with each other causing vibrations to pass between air particles

36
Q

How these tiny particles help is hear sound?

A

They vibrate through a persons ear and vibrate their eardrum

37
Q

What does light travel faster than?

A

Light travels much faster than sound and air

38
Q

What types of waves are sound waves?

A

Longitudinal waves

39
Q

What do longitudinal waves do to the tiny particles (sound)?

A

They cause the particles to vibrate parallel to the direction of wave travel

40
Q

What can the vibrations caused by longitudinal waves do?

A

The
vibrations
can travel through solids, liquids or gases

41
Q

What does the speed of sound depend on?

A

The medium through which it is travelling

42
Q

What is the medium?

A

A material through which a wave can be transmitted (propagate).

43
Q

What is the speed of sound when travelling through air?

A

About 330 metres per second (m/s)

44
Q

What can sound not travel through?

A

A vacuum

45
Q

What is a vacuum?

A

A volume that contains no matter

46
Q

Why can sound not travel through a vacuum?

A

Because there are no particles to carry the vibrations

47
Q

What may change when waves are transmitted at an interface (boundary)

A

It may change its direction

48
Q

What is refraction?

A

Process by which a wave changes speed and sometimes direction upon entering a denser or less dense medium

49
Q

What can all waves be?

A

Refracted

50
Q

What is a ray diagram?

A

Diagram that represents the direction and angle of travel of light.

51
Q

The density of a material is one of the factors that affects….. (refraction)

A

the speed that a wave will be transmitted through it.

52
Q

What does the word “FAST” mean in terms of refraction?

A

F:aster
A:way
S:lower
T:owards

53
Q

What are the 3 things that can happen to Waves arriving at the interface (boundary) between two materials?

A

They can either be
Reflected
Transmitted
Or absorbed

54
Q

What happens to a wave when it is absorbed?

A

Energy is ‘taken-in’ by the material and the internal energy of the material will increase

55
Q

What 3 factors will determine what happens to most of the wave energy?

A

The type of wave,
its properties such as wavelength, and the difference between the two media

56
Q

What has a big effect on how much of the wave’s energy is reflected, absorbed or transmitted at an interface?

A

Wavelength