When the observer moves towards a stationary source with velocity $V_1$,the apparent frequency of the emitted note is $F_1$. When the observer moves away from the source with velocity $V_1$,the apparent frequency is $F_2$. If $V$ is the velocity of sound in air and $F_1 / F_2 = 2$,then $V / V_1$ is equal to:

$A$ source of frequency $150 \, Hz$ is moving in the direction of a person with a velocity of $110 \, m/s$. The frequency heard by the person will be .... $Hz$ (speed of sound in medium $= 330 \, m/s$)

$A$ bus driving along at $39.6 \,km/h$ is approaching a person who is standing at the bus stop,while honking repeatedly at an interval of $30 \,s$. If the speed of sound is $330 \,ms^{-1}$,at what interval will the person hear the horn?

$A$ and $B$ are two sources generating sound waves. $A$ listener is situated at $C$. The frequency of the source at $A$ is $500 \, Hz$. $A$ now moves towards $C$ with a speed of $4 \, m/s$. The number of beats heard at $C$ is $6$. When $A$ moves away from $C$ with a speed of $4 \, m/s$,the number of beats heard at $C$ is $18$. The speed of sound is $340 \, m/s$. The frequency of the source at $B$ is ..... $Hz$.

$A$ sound source is moving towards a stationary listener with $1/10$th of the speed of sound. The ratio of apparent to real frequency is

The driver of a car travelling with speed $30 \ m/s$ towards a hill sounds a horn of frequency $600 \ Hz$. If the velocity of sound in air is $330 \ m/s$,the frequency of the reflected sound as heard by the driver is .... $Hz$