# Waves Flashcards

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1
Q

What is frequency measured in?

A

Hertz (Hz)

2
Q

What is wavelength measured in?

A

Metres (m)

3
Q

What is the wave equation?

A

v = f x lambda Velocity (m/s) = Frequency (Hz) x Wavelength (m)

4
Q

What is a transverse wave?

A

-One that looks like a snake. -The oscillations are at right angles (perpendicular) to the direction of travel -Electromagnetic Waves (No medium)

5
Q

What is a longitudinal wave?

A

-One that has compressions and rarefactions. -The oscillations go in the same direction as the wave. -Sound

6
Q

Give some examples of a transverse wave:

A

-Light -Microwaves -Infrared -Radio -Water waves

7
Q

Give some examples of a longitudinal wave:

A

-Sound -Pressure (Shock) Waves

8
Q

What is wavelength?

A

The distance between two corresponding points on a wave diagram. E.g. From crest to crest.

9
Q

What is amplitude?

A

Amplitude is the length between the node (middle line) and the crest of a wave.

10
Q

What is a crest and a trough?

A

Crest - The top of a wave Trough - The bottom of a wave

11
Q

What do waves do?

A

Transfer energy, not matter. That medium always returns to its original place.

12
Q

What is frequency?

A

The number of wave crests passing a point every second.

13
Q

What is the speed equation?

A

Speed = Distance / Time

14
Q

Waves travelling from low to high density…

A

Slow down and bend towards the normal

15
Q

Waves travelling from high to low density…

A

Speed up and bend away from the normal

16
Q

What happens to wavelength when waves enter a material of higher density?

A

It decreases

17
Q

What do water waves do when going from deep to shallow water?

A

They slow down and bend towards the normal.

18
Q

What is diffraction?

A

The spreading out of waves after passing through a gap.

19
Q

When is diffraction most effective?

A

Wavelength smaller than gap - Little diffraction Wavelength bigger than gap - Lots of diffraction Large wavelength - Lots of diffraction generally

20
Q

What are the parts of the eye?

A
21
Q

What does the iris do in the eye?

A

Controls the amount of light which goes into the eye by expanding and detracting

22
Q

What does the cornea do in the eye?

A
• Protects the eye (aqeous humour)
• Refracts the light to the lens
23
Q

What does the lens do in the eye?

A

Focuses the image onto the retina

24
Q

What do the ciliary muscles do in the eye

A

Control the power of the lens

• More powerful - relaxed (bigger curve)
• Less powerful - contracted (smaller curve)
25
Q

What does the retina do in the eye?

A

Turns light (EM radiation) into an electrical signal

26
Q

What part of the eye sends the electrical signals to the brain?

A

Optic nerve

27
Q

What is another word for being short sighted?

A

Myopia

28
Q

What is the technical term for having long sightedness?

A

Hypermetropia

29
Q

What causes myopia?

A
• Cornea is curved too much
• Lens is too powerful
30
Q

Where does myopia cause the image to be formed?

A

In front of the retina, far objects appear blurred

31
Q

What causes hypermetropia?

A
• Lens or cornea is not powerful enough
32
Q

Where does hypermetropia cause the image to be formed?

A

Behind the retina, near objects appear blurred

33
Q

What is the far point of a persons vision?

A

The furthest distance that an unaided eye can focus a clear image