Q. A train moves towards a stationary observer with speed 34 m/s. The train sounds a whistle and its frequency registered by the observer is $f_1$. If the speed of the train is reduced to 17 m/s, the frequency registered is $f_2$. If speed of sound is 340 m/s, then the ratio $f_1/f_2$ is :


$f_{\text{app}} = f_{0} \left[\frac{V_{2} \pm V_{0}}{V_{2} \mp V_{s}}\right] $
$ f_{1} =f_{0} \left[\frac{340}{340-34}\right] $
$f_{2} = f_{0} \left[\frac{340}{340-17}\right] $
$\frac{f_{1}}{f_{2}} = \frac{340 -17}{340-34} = \frac{323}{306} \Rightarrow \frac{f_{1}}{f_{2}} = \frac{19}{18} $

You must select option to get answer and solution

Questions from JEE Main 2019

Physics Most Viewed Questions

7. The spectrum of an oil flame is an example for ...........

KCET 2010 Dual Nature Of Radiation And Matter