A train standing at the outer signal of a rai | vedclass

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(B) According to the Doppler effect,the apparent frequency $f_{L}$ heard by an observer is given by the formula:$f_{L} = f_{S} \left( \frac{v + v_{L}}

Vedclass · Accepted Answer

$412.5$

Vedclass · Answer

(B) According to the Doppler effect,the apparent frequency $f_{L}$ heard by an observer is given by the formula:$f_{L} = f_{S} \left( \frac{v + v_{L}}{v + v_{S}} ight)$Here,$f_{S} = 400 \ Hz$ is the source frequency,$v = 330 \ ms^{-1}$ is the speed of sound in air,$v_{L} = 0 \ ms^{-1}$ is the velocity of the observer (standing on the platform),and $v_{S} = -10 \ ms^{-1}$ is the velocity of the source (moving towards the observer).Substituting the values:$f_{L} = 400 	imes \left( \frac{330 + 0}{330 - 10} ight)$$f_{L} = 400 	imes \left( \frac{330}{320} ight)$$f_{L} = 400 	imes 1.03125 = 412.5 \ Hz$Thus,the frequency of the sound heard by the observer is $412.5 \ Hz$.

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