Sound waves of wavelength greater than that of audible sound are called

$Assertion :$ Sound travels faster in solids than gases.
$Reason :$ Solids possess greater density than gases.

$A$ 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:

$v_1$ and $v_2$ are the velocities of sound at the same temperature in two monoatomic gases of densities $\rho_1$ and $\rho_2$ respectively. If $\frac{\rho_1}{\rho_2} = \frac{1}{4}$,then the ratio of velocities $v_1$ and $v_2$ will be

Which of the following waves cannot be polarized?

Why is the speed of sound higher in solids and liquids as compared to gases?