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 $= 350 \, m/s$)

The frequency of a sound wave is $n$ and its velocity is $v$. If the frequency is increased to $4n$,the velocity of the wave will be

Which of the following waves is used in sonography?

The speed of a longitudinal wave in a metallic bar is $400 \ m/s$. If the density and Young's modulus of the bar material are increased by $0.5\%$ and $1\%$ respectively, then the speed of the wave is changed approximately to . . . . . . $m/s$.

$A$ source of sound $S$ having frequency $f$. Wind is blowing from source to observer $O$ with velocity $u$. If the speed of sound with respect to air is $C$,the wavelength of sound detected by $O$ is:

$A$ sound wave passing through an ideal gas at $NTP$ produces a pressure change of $0.001 \ dyne/cm^2$ during adiabatic compression. The corresponding change in temperature $(\gamma = 1.5$ for the gas and atmospheric pressure is $1.013 \times 10^6 \ dyne/cm^2)$ is: