At what temperature (in $^\circ C$) will the speed of sound in air be $3$ times its value at $0^\circ C$ (in $^\circ C$)?

Which of the following waves cannot be polarized?

Why can we not have a conversation on the surface of the Moon?

The wavelength of sound in any gas depends upon

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

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: