CP4

Question 1

Define frequency and state the unit

Answer 1

Hz – number of waves passing a point per second

Question 2

Describe how longitudinal waves travel

Answer 2

Movement of energy is parallel to the direction of movement of a longitudinal wave

Question 3

State an example of a longitudinal wave

Answer 3

Sound, seismic P waves

Question 4

Describe how transverse waves travel

Answer 4

Movement of energy is perpendicular (at 90 degrees) to the direction of movement of a transverse wave

Question 5

State examples of transverse waves

Answer 5

Light, water, seismic S waves, all electromagnetic waves

Question 6

What are the two equations that can be used to calculate wave speeds:

Answer 6

1) Speed = distance / time

2) speed = frequency x wavelength

Question 7

A wave travels 10m in 2 seconds. Calculate the speed.

Answer 7

Speed = 10 / 2 = 5m/s

Question 8

A wave has a speed of 330m/s and a wavelength of 16m. Calculate the frequency.

Answer 8

Frequency = 330 / 16 = 20.6 Hz

Question 9

Describe how you could measure the speed of water waves between two buoys floating in the sea

Answer 9

Measure the distance between the buoys; time how long it takes a wave to move between the buoys; speed = distance / time

Question 10

Define refraction

Answer 10

Change of speed and direction of a wave as it enters (or leaves) a medium of a different density

Question 11

What is the normal?

Answer 11

A line at 90 degrees (perpendicular) to the boundary between two materials

Question 12

Describe what happens when a light travels from air to glass

Answer 12

Less dense to more dense so ray refracts towards the normal (light slows down)

Question 13

Describe what happens when a light travels from glass to air

Answer 13

More dense to less dense to light refracts away from the normal (light speeds up)