P5.1.3 - Sound properties and use Flashcards
1
Q
What is refraction?
A
The changing in direction of a wave when its speed changes as a result of going from one medium to another
2
Q
What is the normal?
A
A line at 90 degrees to the surface where the wave hits it
3
Q
What happens to a sound wave at a boundary?
A
It can be:
- reflected (an echo)
- transmitted (and possibly refracted)
- absorbed
4
Q
What is ultrasound?
A
Ultrasound is sound of a frequency greater than 20 000Hz.
5
Q
Are humans are able to hear ultrasound?
A
No but many other animals can
6
Q
How is ultrasound used to make an image of a baby inside a mother?
A
- the transmitter beams ultrasound waves into another
- the waves reflect from the different boundaries
- the machine calculates the distances using time and velocity, and uses those distances to produce an image
7
Q
What is echo-sounding?
A
A process of finding distance using the time for the reflection of a pulse of sound
8
Q
What is sonar?
A
A method or working out the distance to objects or navigating using sound
