1. Progressive Waves

Question 1

Define the term progressive wave

Answer 1

A wave that carries energy from one place to another without transferring any material

Question 2

What is a wave caused by?

Answer 2

Something making particles or fields (e.g. electric or magnetic fields) oscillate at a source

Question 3

Why does the source of the wave lose energy?

Answer 3

The wave is carrying energy away from the source

Question 4

Name 4 ways you can tell waves carry energy

Answer 4

1. EM waves cause things to heat up
2. X-rays and gamma rays knock electrons out of orbit, causing ionisation
3. Loud sounds cause large oscillations of air particles which can make things vibrate
4. Wave power can be used to generate electricity

Question 5

Name 3 behaviours of waves

Answer 5

1. Reflection
2. Refraction
3. Diffraction

Question 6

What happens to a wave during reflection?

Answer 6

The wave is bounced back when it hits a boundary

Question 7

What happens to a wave during refraction?

Answer 7

The wave changes direction as it enters a different medium as a result of the wave speeding up or slowing down

Question 8

What happens to a wave during diffraction?

Answer 8

The wave spreads out as it passes through a gap or round an obstacle

Question 9

How is hearing a sound from around a corner possible?

Answer 9

The sound waves have been diffracted

Question 10

What is meant by the displacement of a vibrating particle in a wave?

Answer 10

How far the vibrating particle has moved from its undisturbed position

Question 11

What is the unit of measurement for displacement?

Answer 11

Metres

Question 12

What is meant by the amplitude of wave?

Answer 12

The maximum magnitude of the displacement of a vibrating particle

Question 13

Where is the amplitude of a wave for a transverse wave measured from?

Answer 13

1. From equilibrium to the peak

2. From equilibrium to the trough

Question 14

What is amplitude measured in?

Answer 14

Metres

Question 15

What is meant by the wavelength of a wave?

Answer 15

The length of one whole wave oscillation or wave cycle

Question 16

Where can the wavelength of a wave be measured from?

Answer 16

Any two adjacent / corresponding points with the same displacement and velocity (e.g. from peak to peak)

Question 17

What is wavelength measured in?

Answer 17

Metres

Question 18

What is meant by the period of a wave?

Answer 18

The time taken for one whole wave cycle

Question 19

What is period measured in?

Answer 19

Seconds

Question 20

What is meant by the frequency of a wave?

Answer 20

1. The number of whole wave cycles per second passing a given point
2. The number of whole wave cycles given out from a source per second

Question 21

What is the frequency measured in?

Answer 21

Hertz (Hz)

Question 22

Define the term phase

Answer 22

A measurement of the position of a certain point along a wave cycle

Question 23

What is meant by phase difference?

Answer 23

The amount by which one wave lags behind another wave or the fraction of a cycle between two vibrating particles

Question 24

What is phase and phase difference measured in?

Answer 24

Angles (degrees or radians)

Question 25

What is the equation linking frequency and period?

Answer 25

f = 1 / T

f = frequency (Hz or s^-1)
T = period (s)