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JEE Main 2014 (11 Apr, Shift 1) · Doppler Effect

Doppler Effect question from JEE Main 2014 (11 Apr, Shift 1)

Q68JEE Main 2014 · 11 APR · SHIFT 1Easy

Doppler Effect

Two factories are sounding their sirens at 800 Hz. A man goes from one factory to other at a speed of 2 m/s. The velocity of sound is 320 m/s. The number of beats heard by the person in one second will be:

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Answer: (d)

Moving from one source to the other: beats $= \dfrac{2fu}{v}$ .
$= \dfrac{2 \times 800 \times 2}{320} = 10$
So the answer is (d) 10.

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