Which of the following cannot be polarised?

If at the same temperature and pressure,the densities of two diatomic gases are respectively $d_1$ and $d_2$,then the ratio of the velocities of sound in these gases will be

The speed of sound in oxygen $(O_2)$ at a certain temperature is $460 \,ms^{-1}$. The speed of sound in helium $(He)$ at the same temperature will be (assume both gases to be ideal): (in $\,ms^{-1}$)

Why are the speeds of longitudinal and transverse waves in a solid different? Explain.

The speed of sound in air is independent of its:

Consider the sound wave travelling in ideal gases of $He$,$CH_4$,and $CO_2$. All the gases have the same ratio $\frac{P}{\rho}$,where $P$ is the pressure and $\rho$ is the density. The ratio of the speed of sound through the gases $V_{He}: V_{CH_4}: V_{CO_2}$ is given by