A car \(P\) travelling at \(20\,ms ^{-1}\) sounds its horn at a frequency of \(400\,Hz\). Another car \(Q\) is travelling behind the first car in the same direction with a velocity \(40\,ms ^{-1}\). The frequency heard by the passenger of the car \(Q\) is approximately \(.......\,Hz\) [Take, velocity of sound \(=360\,ms ^{-1}\) ]

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Answer & Solution

Correct Answer

(B) \(421\)

Step-by-step Solution

Detailed explanation

\(f=f_0\left(\frac{c+v_0}{c+v_s}\right)\)

\(f=400\left(\frac{360+40}{360+20}\right)\)

\(f=421\,Hz\)

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