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

The enclosed air inside a closed box of rigid walls has pressure $P_1$. The density of air inside this box is constant. On heating the gas, the pressure of the enclosed air is increased from $P_1$ to $P_2$. Now it is observed that the sound travels $1.4$ times faster than at pressure $P_1$. The ratio $P_2/P_1$ is:

$A$ 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:

$A$ plane sound wave passes from medium $1$ into medium $2$. The speed of sound in medium $1$ is $200 \, m/s$ and in medium $2$ is $100 \, m/s$. The ratio of the amplitude of the transmitted wave to that of the incident wave is:

The figure below shows pressure variation in two different sound waves in air with time at a given position. Both the figures are drawn to the same scale. Which of the following statements is true?

The ratio of the speed of sound in nitrogen gas to that in helium gas,at $300 K$ is