An ambulance moves around a large roundabout with its sirens on. For a person standing at the center of roundabout, the frequency of ambulance siren heard will be
a) Equal to actual siren frequency
b) Less than actual siren frequency
c) Greater than actual siren frequency
d) Changing frequency as ambulance moves in a roundabout
Answers
Answer:
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Answer:
(D) Changing as the ambulance moves.
Explanation:
This is because of the Doppler effect, which is the change in frequency or wavelength of a wave in relation to an observer who is moving relative to the source of the wave.
As the ambulance moves towards the person standing in the center of the round-about, the sound waves of the siren get compressed, which increases the frequency of the sound waves heard by the person. This means that the person hears a higher frequency than the actual siren frequency.
Conversely, as the ambulance moves away from the person, the sound waves of the siren get stretched, which decreases the frequency of the sound waves heard by the person. This means that the person hears a lower frequency than the actual siren frequency.
Therefore, the frequency of the ambulance siren heard by a person standing in the center of the round-about will be changing as the ambulance moves, and it will not be equal to the actual siren frequency