P12 Waves Flashcards

1
Q

Equation for wavespeed?

A

Wavespeed = frequency x wavelength

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2
Q

Transverse waves

A

Wave oscillations are perpendicular to direction of energy transfer

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3
Q

Longitudinal waves

A

Wave oscillations are parallel to direction of energy transfer

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4
Q

What happens when wave arrives at a boundary?

A

Waves can either be absorbed, transmitted or reflected

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5
Q

What happens when a wave is reflected in a single direction by a smooth surface?

A

Specular relection

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6
Q

What does the size of the amplitude of the wave mean?

A

The larher the amplitude of the wave, the more energy the wave carries

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7
Q

What is frequency

A

The time taken for each wave to pass a fixed point measured in hertz

1 wave crest passing a point in 1 second is equal to 1Hz

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8
Q

What is a period of a wave

A

Time taken for each wave to pass a fixed point

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9
Q

Equation that links frequecny and period

A

Period (seconds) = 1
___________________
Frequency (Hz)

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10
Q

Equation for wavespeed

A

Wave speed (m/s) = Frequency (Hz) X Wavelength (m)

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11
Q

Example of a transverse wave

A

Ripples on surface of water

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12
Q

Example of longitudinal waves

A

Sound waves travelling through air

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13
Q

What is the amplitude of a wave

A

The maximum displacement point of a wave from it’s undisturbed position

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14
Q

What is the method to find speed of sound waves in a ir?

A

2 people
Stand far away from eachother in a field
Measure distance between eachother
Get 1 person to clash cymbals
Other person holds stopwatch
Start stopwatch when you see cymbals clash and stop when you hear the sound
Repeat to get an average time interval

Speed = distance divided by time

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15
Q

What is refraction

A

When the wave crosses a boundary at a non-zero angle to the boundary, the wave will change in speed and direction

If wavefronts move slower at the non-zero angle boundary the wavefront will be at a smaller angle to the boundary and closer together

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16
Q

Rules for refracted waves

A

Refracted wave and incident wave will have the same frequency but travel at different speeds so they have different wavelengths

17
Q

What happens when a wave is absorbed by a substance?

A

Ehen a wave is absorbed by a substance, the substance will:

Gains energy from the waves
Therefore heat the substance will heat up

18
Q

What happens when a wave is transmitted by a substance?

A

The waves are transmitted

E.g. glass mostly transmits light waves

19
Q

Learn wave practical

A

Stupid!

20
Q

What is the normal range of human hearing?

A

20Hz - 20kHz

21
Q

How can humans hear?

A

Sound waves can travel through solids causing vibrations in the
solid.
Within the ear, sound waves cause the ear drum and other parts to
vibrate which causes the sensation of sound. The conversion of
sound waves to vibrations of solids works over a limited frequency
range. This restricts the limits of human hearing.

22
Q

What are ultrasound waves?

A

Sound waves that have a frequency higher than the limit of human hearing

23
Q

How do ultrasound scans work?

A
  • Ultrasound waves are partially reflected when they meet a boundary
  • The time taken for the reflections to reach a detector can be used to determine how far away such a boundary is.
  • This allows ultrasound waves to be used for both medical and industrial imaging.
24
Q

What are the 2 different types of seismic waves?

A

Primary waves
And
Secondary waves

25
Q

What are Primary seismic waves?

A
  • P-waves
  • Longitudinal seismic waves
  • Travel at different speeds through solids and liquids
26
Q

What are Secondary seismic waves?

A
  • S-waves
  • Transverse waves
  • Cannot travel through a liquid
27
Q

What is a transverse wave?

A

Oscillations of transverse wave are perpendicular to the direction of energy transfer

28
Q

What is a longitudinal wave?

A

Oscillations of a Longitudinal wave are parallel to the direction of energy transfer

29
Q

What is echo sounding?

A

Uses high frequency sound waves to measure depth of water and detect objects in deep water

30
Q

How are sound waves produced by an object vibrating in air?

A

Vibrating object pulls and pushes repeatedly on air
This sends out vibrations of air of compressions and rarefractions
The waves are longitudinal

31
Q

Why is it important the human tissue does not absorb ultrasound waves in medical scanners?

A

If it was absorbed, the wave wouldn’t be detected