$A$ source of sound of frequency $450 \text{ cycles/sec}$ is moving towards a stationary observer with $34 \text{ m/sec}$ speed. If the speed of sound is $340 \text{ m/sec}$,then the apparent frequency will be ..... $\text{cycles/sec}$.

Two sirens situated one kilometer apart are producing sound of frequency $330 \ Hz$. An observer starts moving from one siren to the other with a speed of $2 \ m/s$. If the speed of sound is $330 \ m/s$,what will be the beat frequency heard by the observer?

Two passenger trains moving with a speed of $108\, km/h$ cross each other. One of them blows a whistle whose frequency is $750\, Hz$. If the speed of sound is $330\, m/s$,then the passengers sitting in the other train,after the trains cross each other,will hear a sound whose frequency is .... $Hz$.

Two cars are moving towards each other at the speed of $50 \,m/s$. If one of the cars blows a horn at a frequency of $250 \,Hz$, the wavelength of the sound perceived by the driver of the other car is (Speed of sound in air $= 350 \,m/s$) (in $\,cm$)

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

When both source and listener are approaching each other,the observed frequency of sound is given by (where $V$ is the speed of sound,$V_L$ and $V_S$ are the velocities of the listener and source respectively,and $n_0$ is the radiated frequency):