$A$ man stands in front of a hillock and fires a gun. He hears an echo after $1.5\, s$. The distance of the hillock from the man is ...... $m$ (velocity of sound in air is $330\, m/s$).

Mention the audible frequency range for humans.

$A$ sound wave is travelling with a frequency of $50 \,Hz$. The phase difference between two points in the path of the wave is $\frac{\pi}{3} \,rad$. The distance between those two points is (Velocity of sound in air $=330 \,m/s$) (in $m$)

$A$ person in front of a mountain is beating a drum at the rate of $40$ per minute and hears no distinct echo. If the person moves $90 \, m$ closer to the mountain,he has to beat the drum at $60$ per minute to not hear any distinct echo. The speed of sound is .............. $ms^{-1}$.

The mass of one mole of a gas is $22.4 \times 10^{-3} \ kg$ and its specific heat ratio is $1.6$. The speed of sound in the gas at $STP$ is nearly: (in $m/s$)

Which of the following cannot be polarised?