An engine is moving with uniform speed along a circular track emitting a sound of frequency $400\, Hz$ as shown in the figure. The speed of the engine is $30\, m/s$ and the speed of sound is $330\, m/s$. An observer is standing inside the track. The maximum frequency observed by the observer is

An observer standing at a station observes a frequency of $219 \, Hz$ when a train approaches and $184 \, Hz$ when the train goes away from him. If the velocity of sound in air is $340 \, m/s$,then the velocity of the train and the actual frequency of the whistle will be:

$A$ car blowing a horn of frequency $350\, Hz$ is moving towards a wall with a speed of $5\, m/s$. The beat frequency heard by a person standing between the car and the wall is ..... $Hz$ (speed of sound in air $= 350\, m/s$).

$A$ siren placed at a railway platform is emitting sound of frequency $5 \text{ kHz}$. $A$ passenger sitting in a moving train $A$ records a frequency of $5.5 \text{ kHz}$ while the train approaches the siren. During his return journey in a different train $B$,he records a frequency of $6.0 \text{ kHz}$ while approaching the same siren. The ratio of the velocity of train $B$ to that of train $A$ is

$A$ car moving towards a wall at a velocity of $72 \,km/hr$ sounds a horn of frequency $124 \,vib/sec$. What frequency will the driver hear? (Speed of sound in air = $330 \,ms^{-1}$)

$A$ train whistling at a constant frequency $n$ is moving towards a station at a constant speed $v_s$. The train goes past a stationary observer on the station. The frequency $n'$ of the sound as heard by the observer is plotted as a function of time $t$. Identify the correct curve.