S3 Physics -

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Waves (I)
S3 Physics -
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1. What is meant by the term ultrasound
sound waves with a frequency above 20,000Hz
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2. What is the speed of light in air?
300,000,000ms-1
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3. A car has a parking sensor that emits
ultrasound waves. They have a frequency of 40kHz
..Calculate their wavelength
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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.
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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
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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
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7. What is meant by the frequency of a wave?
Number of complete waves that pass a point in one
second
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8. Are light waves transverse or longitudinal
waves?
Transverse
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9.What is the frequency range of human hearing?
20Hz-20,000Hz
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What is the threshold of pain for the human ears?
130dB
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11. Give a use of ultrasound in medicine.
Scanning an unborn baby in the womb
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12. True or falseLong wave are diffracted more
than short waves?
True
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13. How could we protect our hearing from
becoming damaged?
Wear ear muffs (ear protectors) that absorb some
of the sound energy.
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14. Which sound has a higher pitch a high
frequency wave or a low frequency wave?
High frequency
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15. Why can sound not travel in a vacuum?
There are no air particles to carry the
vibrations.
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16. The frequency of a wave is 200Hz, Calculate
the Period of this wave.

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