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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