# P1 - Waves Flashcards

0
Q

What is a transverse wave?

A

These waves vibrate perpendicular to the direction of energy transfer of the wave.

1
Q

What can waves be used for?

A

Energy and information transfer.

2
Q

What type of wave is an electromagnetic wave?

A

Transverse

3
Q

What is a longitudinal wave?

A

The wave vibrates parallel to the direction of energy transfer of the wave.

4
Q

What type of wave is a sound wave?

A

Longitudinal

5
Q

What type of wave is a mechanical wave.

A

A mechanical wave can be transverse of longitudinal.

6
Q

What is needed for a mechanical wave to vibrate?

A

A medium

7
Q

How fast do EM waves travel?

A

300,000,000 m/s

8
Q

Give three examples of EM waves.

A

9
Q

What are the vibrations of a longitudinal wave also known as?

A

Compressions

10
Q

What is the amplitude of a wave?

A

The height or depth of a wave from the position of rest.

11
Q

What is the frequency of a wave?

A

The number of waves that pass a point in one second.

12
Q

What is a wave’s wavelength?

A

The distance from one crest to another.

13
Q

What is the formula for wave speed, wavelength and frequency?

A

v=f λ

14
Q

What is the unit of frequency?

A

Hertz

15
Q

What is the normal in a diagram showing light rays?

A

A line drawn at a point perpendicular to the mirror.

16
Q

What is an angle of incidence?

A

The angle between the incident ray and the normal.

17
Q

What is an angle of reflection?

A

The angle between the reflected ray and the normal.

18
Q

What is the law of reflection?

A

The angle of incidence equals the angle of reflection.

19
Q

What is a plane mirror?

A

A perfectly flat mirror.

20
Q

What is a virtual image?

A

An upright and laterally inverted image.

21
Q

How is a real image formed?

A

Focusing light onto a screen.

22
Q

What is refraction?

A

The change of direction of waves when they travel across a boundary.

23
Q

What happens to a light ray when it travels from air to glass?

A

The angle of refraction is less than the angle of incidence. The ray travels towards the normal.

24
Q

What happens to a light ray when travelling from glass into air?

A

The angle of refraction is more than the angle of impedance.

25
Q

What is diffraction?

A

The spread of waves when passing through a gap or round the edge of an obstacle.

26
Q

How does the width of the gap effect the diffraction of waves?

A

The narrower the gap is, the greater the diffraction.

27
Q

Why can radio and TV reception be poor in hilly areas?

A

If the radio waves do not diffract enough, the waves won’t reach the aerial on a house.

28
Q

How does diffraction effect optical imaging?

A

If light diffracts too much, the image is of poor quality.

29
Q

How does diffraction effect ultrasonic imaging?

A

If the transmitter is too narrow, the waves spread out making the image unclear.

30
Q

What is the range of human hearing?

A

20-20,000 Hz

31
Q

What are sound waves?

A

Vibrations that travel through a medium.

32
Q

What are echoes?

A

Sound waves reflected from a smooth, hard surface.

33
Q

How can sound waves be produced?

A

Any object vibrating in air makes layers of air nearby vibrate.

34
Q

What is the speed of sound?

A

330ms^1

35
Q

How does air temperature affect the speed of sound?

A

The warmer the air, the greater the speed of sound.

36
Q

Where does sound refraction take place in air?

A

The boundaries between layers of air at different temperatures.

37
Q

Which way does sound reflect in the day and why?

A

In daytime, sound refracts upwards because the air near the ground is warmer than the air higher up.

38
Q

What determines the pitch of a note?

A

The pitch of a note increases with the frequency of sound waves.

39
Q

What happens to the loudness of a note as the amplitude increases?

A

The loudness of a note increases with the amplitude of the sound waves.

40
Q

How are sound waves created by musical instruments?

A

Vibrations made by the instrument when it is played produce sound waves.