Start Free Mock LoginAlready registered? Login here

Physics - Sound Wave Question with Solution | TestHub

PhysicsSound WaveWavesMedium2 minQB

PhysicsMediumnumerical

When a train is approaching the observer, the frequency of the whistle is 100 Hz. When it has passed the observer, it is 50 Hz. Calculate the frequency when the observer moves with the train.

Answer:

66.70

Solution:

$\frac{f _{0} v}{v - u} = 100$ and $\frac{f _{0} v}{v + u} = 50$ give $v + u = 2 (v - u)$ , so $u = v /3$ and $f_{0} = 100 \times \frac{2}{3} = 66.7$ Hz. An observer moving with the train has no relative motion with the source, so he hears $f_{0}$ .

Stream:JEESubject:PhysicsTopic:Sound WaveSubtopic:Waves

⏱ 2mℹ️ Source: QB

Doubts & Discussion

Loading discussions...