## Question

A whistle emitting a sound of frequency 440 Hz is tied to a string of 1.5 m length and rotated with an angular velocity of 20 rad/s in the horizontal plane. Then the range of frequencies heard by an observer stationed at a large distance from the whistle will be:

(*v* = 330 m/s):

### Solution

403.3 Hz to 484.0 Hz

Frequency heard by the observer will be maximum when the source is in position *D*. In this case, source will be approaching towards the stationary observer, almost along the line of sight (as observer is stationed at a large distance).

Similarly, frequency heard by the observer will be minimum when the source reaches at the position *B*. Now, source will be moving away from the observer.

#### SIMILAR QUESTIONS

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