Waves Flashcards

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0
Q

When are longitudinal waves produced

A

When the vibrations are parallel to the axis

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1
Q

What do waves transfer?

A

Energy (NOT matter)

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4
Q

Compression

A

Region where the particles are closer

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5
Q

A region where the particles are farther apart

A

Rarefaction

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6
Q

What is the relationship between the amount of diffraction and wavelength

A

The longer the wavelength the more diffraction there is

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7
Q

Why is red light diffracted the most

A

Longer wavelength

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8
Q

What is the time period of a wave and what is it measured in

A

The time it takes for a source to produce one wave, measured in seconds

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9
Q

What is the frequency of a wave & what is it measured in?

A

The number of waves produced each second, hertz

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10
Q

What is the equation relating frequency (f) and time period (T)

A

f = 1 ➗ T
Or
T = 1➗f

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11
Q

The height of a sound wave is related to

A

The volume

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12
Q

The greater the amplitude..

A

The louder the sound

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13
Q

The amplitude

A

The maximum displacement of the wave from the undisturbed/equilibrium position

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14
Q

The number of waves produced is related to

A

The pitch or frequency

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15
Q

The wave equation

A

Wave speed = frequency x wavelength

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16
Q

Wavelength

A

The distance in metres from any point on the wave to where it repeats

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17
Q

When are transverse waves produced

A

When the vibrations are at right angles to the direction of energy

18
Q

What is a wave

A

A vibration or disturbance transmitted through a material (a medium) or through space

19
Q

Light waves are

A

Transverse

21
Q

Shortest wavelength, highest frequency, highest energy

A

Gamma rays

22
Q

Properties that all electromagnetic waves share 2

A

Transverse waves

Can travel through a vacuum

23
Q

Longest wavelength, lowest frequency & lowest energy

A

Radio waves

24
Q

Trough

A

Point on a wave with the lowest displacement

25
Q

What is refraction

A

The bending of light when it enters a different medium

26
Q

Why does the refractive index have no units?

A

It’s a ratio

27
Q

When does TIR occur

A

When the angle of refraction is greater than 90 and the light cannot leave the medium

28
Q

What’s normal?

A

An imaginary line that’s at right angles to the surface (at the point where light hits the surface)

29
Q

Law of reflection

A

The angle of incidence equals the angle of reflection

30
Q

Critical angle

A

The angle of incidence above which TIR occurs

31
Q

Why do diamonds sparkle

A

Diamond has a very high refractive index and so a low critical angle which leads to more internal reflections

32
Q

Why is a semicircular block used to demonstrate total internal reflection

A

The incident ray always hits the curved side of the block at 90* so there are no refraction effects as it enters the block, only when it leaves from the straight edge

33
Q

Properties of image in plane mirror (4)

A
  • laterally inverted
  • virtual
  • same size
  • as far behind the mirror as the object is in front
34
Q

Explain why a ray entering a glass block changes direction each time it crosses the air/glass boundary

A

As the ray of light enters the glass block, it slows down and is refracted towards the normal.
As the Ray leaves the glass block, its speed increases and it is refracted away from the normal

35
Q

Why is white light dispersed

A

White light is composed of a mixture of colours. Because each colour travels at a different speed through the prism, they are refracted through different angles

36
Q

Advantage of using prisms in a periscope rather than plane mirrors

A

The final image created by a prismatic periscope is likely to be sharper and brighter

37
Q

What would happen to a ray of light inside an optical fibre if the outer glass had a higher optical density than the inner glass?

A

If the outer glass of an optical fibre had a higher refractive index, light within the fibre striking the boundary would be refracted and escape through the sides

38
Q

Médical application of optical fibres

A

Endoscopes allow doctors to see inside the body, and make keyhole surgery possible