The velocity of sound in air at $20^{\circ} C$ and $1 \text{ atm}$ pressure is $344.2 \text{ m/s}$. At $40^{\circ} C$ and $2 \text{ atm}$ pressure, the velocity of sound in air is approximately: (in $\text{ m/s}$)

Which of the following statements are wrong about the velocity of sound in air?

$A$ train,standing in a station yard,blows a whistle of frequency $400 \, Hz$ in still air. The wind starts blowing in the direction from the yard to the station with a speed of $10 \, m/s$. Given that the speed of sound in still air is $340 \, m/s$. Mark the $INCORRECT$ statement:

If $v_m$ is the velocity of sound in moist air and $v_d$ is the velocity of sound in dry air,under identical conditions of pressure and temperature,then:

Find the frequency of the minimum distance between a compression and a rarefaction of a wire. If the length of the wire is $1\, m$ and the velocity of sound in air is $360\, m/s$,find the frequency in $sec^{-1}$.

An earthquake generates both transverse $S$ and longitudinal $P$ waves in the earth with speeds $4.5 \,km/s$ and $8.0 \,km/s$, respectively. $A$ seismograph records that the first $P$-wave arrives $3.5 \,min$ earlier than the first $S$-wave. From the seismograph, the epicentre of the earthquake is located at a distance of: (in $\,km$)