4.12-4.16 Ultrasound and Infrasound

Question 1

What is the range at which the human ear can hear?

Answer 1

20-20000HZ

Question 2

What are waves with a frequency greater than 20,000Hz known as?

Answer 2

Ultrasound

Question 3

What are sound waves with a frequency of less than 20Hz known as?

Answer 3

Infrasound

Question 4

How are ultrasound waves used in sonar?

Answer 4

Pulse of ultrasound is sent below a ship and the time taken for it to reflect and reach the ship can determine the depth
This is used to workout wether a shoal of fish are below the ship or how far the seabed is below the ship

Question 5

Is foetal scanning invasive or harmful?

Answer 5

It is not invasive or harmful

Question 6

How are ultrasound waves used in foetal scanning?

Answer 6

.Used to create an image of the foetus allowing measurements to be made to see if its developing normally
.this works as ultrasound waves reflect at each boundary-used to work out image

Question 7

How can infrasound waves be used to investigate the Earths core?

Answer 7

.On the opposite side of the Earth to an earthquake only P waves can be detected
.Suggesting the core of the Earth is liquid as S waves cannot penetrate it

Question 8

How do we know the Earths core is liquid?

Answer 8

S waves cannot penetrate the core

Question 9

If the velocity of a wave changes what must also change?

Answer 9

.The frequency or wavelength (Or Both)

Question 10

When a sound wave enters a different material what changes?

Answer 10

The wavelength and velocity