A bat moving at 10 ms − 1 towards a wall sends a sound signal of 8000 Hz towards it. On reflection it hears a sound of frequency f . The value of f in Hz is close to ( speed of sound = 320 ms − 1 )

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TestHub · Accepted Answer

We can assume that reflected wave is due to image of $B$ coming with same speed in opposite direction

Observer

$f = \frac{v + 10}{v - 10} \times f_{0}$

$= \frac{320 + 10}{320 - 10} \times 8000$

$= \frac{330}{310} \times 8000$

$= \frac{33}{31} \times 8000$

$= 8516 H z$

Physics - Sound Wave Question with Solution | TestHub

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