$A$ train moves towards a stationary observer with speed $34\, m/s$. The train sounds a whistle and its frequency registered by the observer is $f_1$. If the speed of the train 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

$A$ siren placed at a railway platform is emitting a sound of frequency $5 \text{ kHz}$. $A$ passenger sitting in a moving train $A$ records the frequency of the siren as $5.5 \text{ kHz}$. During his return journey by train $B$,he records the frequency of the siren as $6 \text{ kHz}$. The ratio of the speed of train $B$ to that of train $A$ is

$A$ vehicle sounding a whistle of frequency $256 \,Hz$ is moving on a straight road towards a hill with a velocity of $10 \,ms^{-1}$. The number of beats per second observed by a person travelling in the vehicle is (velocity of sound $= 330 \,ms^{-1}$).

Obtain the equation of frequency observed by a moving observer and a stationary source.

$A$ car moves towards a hill with speed $v_c$. It blows a horn of frequency $f$ which is heard by an observer following the car with speed $v_o$. The speed of sound in air is $v$.

$A$ source of sound of frequency $500 Hz$ is moving towards an observer with velocity $30 m/s$. The speed of sound is $330 m/s$. The frequency heard by the observer will be .... $Hz$