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(C) The speed of the train (source and observer) is $v_T = 220\, m s^{-1}$.The speed of sound in air is $v = 330\, m s^{-1}$.The source (train) emits

Vedclass · Accepted Answer

$5000$

Vedclass · Answer

(C) The speed of the train (source and observer) is $v_T = 220\, m s^{-1}$.The speed of sound in air is $v = 330\, m s^{-1}$.The source (train) emits a frequency $f_0 = 1000\, Hz$.First,the sound reaches the stationary object. The frequency received by the object is $f_1 = f_0 \left( \frac{v}{v - v_T} ight)$.Then,the object reflects this sound back to the moving train. The train acts as an observer moving towards the reflected sound source. The frequency detected by the driver is $f' = f_1 \left( \frac{v + v_T}{v} ight)$.Substituting $f_1$ into the equation for $f'$,we get $f' = f_0 \left( \frac{v}{v - v_T} ight) \left( \frac{v + v_T}{v} ight) = f_0 \left( \frac{v + v_T}{v - v_T} ight)$.Calculating the value: $f' = 1000 \left( \frac{330 + 220}{330 - 220} ight) = 1000 \left( \frac{550}{110} ight) = 1000 	imes 5 = 5000\, Hz$.

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