The echo of a gun shot is heard $8 \, s$ after the gun is fired. How far from the shooter is the surface that reflects the sound (in $, m$)? (Velocity of sound in air $= 350 \, m/s$)

$SONAR$ emits which of the following waves?

Frequency range of the audible sounds is

If the density of oxygen is $16$ times that of hydrogen,what will be the ratio of their corresponding velocities of sound waves?

$A$ 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 $10\,ms^{-1}$. What will be the frequency and speed of sound for an observer? (The speed of sound in still air is $340\,ms^{-1}$)

The speed of sound waves in a fluid depends upon: