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1. What is meant by the term: ultrasound

sound waves with a frequency above

20,000Hz

answer

2. What is the speed of light in air?

300,000,000ms-1

answer

3. A car has a parking sensor that emits ultrasound waves. They have a frequency of 40kHz ..Calculate their wavelength

answerm

f

v

3105.8

000,40

340

4. A car stops 1.7m from a wall. Calculate the time for an ultrasound pulse from a parking sensor to reflect from the wall and return to the car.

answer

s

v

dt

01.0

340

4.3

5. The car moves further from the wall, what happens to the time taken for the

Ultrasonic wave to return to the car?

The time will increase as it has further to travel

answer

6. Why can we get a good radio signal in hilly areas but a poor TV signal?

Radio waves have a longer wavelength than TV waves and diffract more

answer

7. What is meant by the frequency of a wave?

Number of complete waves that pass a point in

one second

answer

8. Are light waves transverse or longitudinal waves?

Transverse

answer

9.What is the frequency range of human hearing?

20Hz-20,000Hz

answer

10. What is the threshold of pain for the human ears?

130dB

answer

11. Give a use of ultrasound in medicine.

Scanning an unborn baby in the womb

answer

12. True or false…Long wave are diffracted more than short waves?

TrueTrue

answer

13. How could we protect our hearing from becoming damaged?

Wear ear muffs (ear protectors) that absorb

some of the sound energy.

answer

14. Which sound has a higher pitch: a high frequency wave or a low frequency wave?

High frequencyHigh frequency

answer

15. Why can sound not travel in a vacuum?

There are no air particles to carry the vibrations.

answer

16. The frequency of a wave is 200Hz, Calculate the Period of this wave.

•.

answer

s

fT

005.0200

1

1