A train,standing in a station yard,blows a wh | vedclass

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(C) The frequency of sound heard by an observer depends on the relative motion between the source and the observer. Since both the train (source) and

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The frequency of sound as heard by the observer standing on the platform will increase.

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(C) The frequency of sound heard by an observer depends on the relative motion between the source and the observer. Since both the train (source) and the observer are stationary relative to the ground,the frequency remains $400 \, Hz$. Thus,statement $(c)$ is incorrect.The speed of sound in the presence of wind is given by $v' = v + w$,where $v = 340 \, m/s$ is the speed of sound in still air and $w = 10 \, m/s$ is the wind speed. So,$v' = 340 + 10 = 350 \, m/s$. Thus,statement $(b)$ is correct.The wavelength $\lambda$ is given by $\lambda = \frac{v'}{f}$. Since $v'$ increases to $350 \, m/s$ while $f$ remains $400 \, Hz$,the wavelength $\lambda$ increases compared to the case in still air. Thus,statement $(d)$ is correct.

$A$ train,standing in a station yard,blows a whistle of frequency $400 \, Hz$ in still air. The wind starts blowing in the direction from the yard to the station with a speed of $10 \, m/s$. Given that the speed of sound in still air is $340 \, m/s$. Mark the $INCORRECT$ statement:

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