A train is moving at $30\,m{s^{ - 1}}$ in still air the frequency of the locomotive whistle is 500Hz and the speed of sound is $345\,m{s^{ - 1}}.$ The apparent wavelengths of sound in front of and behind the locomotive are respectively.

An observer is moving away from source of sound of frequency $100\,\,Hz$. This speed is $33\,\,m/s$. If speed of sound is $330\,\,m/s$, then the observed frequency is

Two open organ pipes gives $4\,\,beats/\sec$ when sounded together in their fundamental nodes. If the length of the pipe are $100\,\,cm$ and $102.5\,\,cm$ respectively, then the velocity of sound is :

What should be the velocity of a sound source moving towards a stationary observer so that apparent frequency is double the actual frequency (Velocity of sound is $v$)

The apparent wavelength of the light from a star moving away from the earth is $0.2\,\,\%$ more than its actual wavelength. Then the velocity of the star is

A source of frequency $n$ given $5$ beats ${{\rm{s}}^{ - 1}}$, when sounded with a source of frequency $200$ ${{\rm{s}}^{ - 1}}$. The second harmonic ($2n$) gives $10$ beats ${{\rm{s}}^{ - 1}}$, when sounded with a source of frequency 420 ${{\rm{s}}^{ - 1}}$. $n$ is equal to

A sound source of frequency $170\,\,Hz$ is placed near a wall. A man walking from a source towards the wall finds that there is a periodic rise and fall of sound intensity. If the speed of sound in air is $340\,\,m/s$. then distance (in metres) separating the two adjacent position of minimum intensity is

A train is approaching with velocity $25\,\,m{s^{ - 1}}$ towards a pedestrian standing on the track, frequency of horn of train is $1\,{\rm{ }}kHz$. Frequency heard by the pedestrian is $\left( {v = 30\,\,m{s^{ - 1}}} \right)$

Two whistles $A$ and $B$ produce notes of frequencies $660\,\,Hz\,\,and\,\,596\,\,\,Hz$ respectively. There is a listener at the mid-point of the line joining them. Now the whistle $B$ and the listener start moving with speed $30\,\,m/s$ away from the whistle $A$. If speed of sound be $330\,\,m/s$, how many beats will be heard by the listener

The source of sound generating a frequency of $3\,\,kHz$ reaches an observer with a speed of $0.5$ times, the velocity of sound in air. The frequency heard by the observer is

A train moves towards a stationary observer with speed $34\,\,m{s^{ - 1}}$. The train sounds a whistle and its frequency registered by the observer is ${v_1}$. If the train’s speed is reduced to $17\,\,m{s^{ - 1}}$, the frequency registered is ${v_2}$. If the speed of sound is $340\,\,m{s^{ - 1}}$, then the ratio ${v_1}/{v_2}$ is