P5.1.3

Question 1

What happens to a sound wave as it passes a boundary?

Answer 1

It is refracted

Question 2

What happens to a sound wave when it passes a boundary into a medium where its velocity increases?

Answer 2

Refracts away from the normal
Wavelength increases
Frequency stays the same
Therefore velocity increases.

Question 3

What happens to a sound wave that hits a barrier at 0 degrees?

Answer 3

It will speed up but not change direction.

Question 4

What 3 things can happen to a wave at a boundary?

Answer 4

Reflected (e.g. echo)
Transmitted (refracted)
Absorbed

Question 5

What is the frequency of ultrasound?

Answer 5

> 20,000Hz, dogs can hear, we can’t

Question 6

Explain a use of ultrasound.

Answer 6

Pre-natal scanning
Transmitter beams ultrasound into mother, reflected off of different boundaries, machine calculates distances using time and velocity to produce an image.

Question 7

What are the uses of ultrasound?

Answer 7

Find kidney stones, monitor blood flow, baby scans, water depth.

Question 8

What is sonar?

Answer 8

Sound navigation and range

Method used to work out distance to objects or navigate using sound.

Question 9

How are ultrasound waves used to measure water depth?

Answer 9

Sends ultrasound wave, calculates time taken for echo to be received to work out depth from velocity.