$A$ person feels a $2.5\%$ difference in the frequency of a motor-car horn. If the motor-car is moving towards the person and the velocity of sound is $320\, m/s$,then the velocity of the car will be:

The frequency changes by $10\%$ as a sound source approaches a stationary observer with constant speed $v_s$. What would be the percentage change in frequency as the source recedes from the observer with the same speed? (Given that $v_s < v$,where $v$ is the speed of sound in air)

$A$ car sounding its horn at $480\,Hz$ moves towards a high wall at a speed of $20\,m/s$. If the speed of sound is $340\,m/s,$ the frequency of the reflected sound heard by the passenger sitting in the car will be the nearest to ..... $Hz$.

An observer moves towards a stationary source of sound with a velocity of one-fifth of the velocity of sound. The percentage increase in the apparent frequency is (in $\%$)

$A$ source of sound is travelling towards a stationary observer. The frequency of sound heard by the observer is three times the original frequency. If the velocity of sound is $v \ m/s$,the speed of the source will be:

Match Column-$A$ with Column-$B$.

Column-$A$	Column-$B$
$(a)$ When source of sound and listener move towards wall.	$(i)$ Listener would hear a sound with same frequency as that of source.
$(b)$ When source of sound and listener move away from each other.	$(ii)$ Listener would hear a sound with frequency smaller than that of source.
	$(iii)$ Frequency of echo would be greater than that of source.