The ratio of densities of nitrogen and oxygen is $14:16$. The temperature at which the speed of sound in nitrogen will be the same as that in oxygen at $55^oC$ is ..... $^oC$.

The velocity of sound is $v_s$ in air. If the density of air is increased to $4$ times,then the new velocity of sound will be

Sound waves travel fastest in

Which of the following statements is correct?

$A$ tuning fork of frequency $220 \,Hz$ produces sound waves of wavelength $1.5 \,m$ in air at $N.T.P$. The increase in wavelength when the temperature of air is $27^{\circ} C$ is nearly $\left(\sqrt{\frac{300}{273}}=1.05\right)$ (in $\,m$)

The depth of the sea is measured by means of an echo. If the time between the moment the sound is produced and received is $3.52 \,s$, then the depth of the sea is (The compressibility of sea water is $4.84 \times 10^{-10} \,m^2 \,N^{-1}$ and its density is $1024 \,kg \,m^{-3}$): (in $km$)