Which of the following waves cannot be polarized?

The speed of sound in air is independent of its:

What is the distance between consecutive condensation and rarefaction in longitudinal waves?

Out of hot moist air and dry cold air,in which does sound travel faster?

Assume that the displacement $(s)$ of air is proportional to the pressure difference $(\Delta p)$ created by a sound wave. Displacement $(s)$ further depends on the speed of sound $(v)$,density of air $(\rho)$,and the frequency $(f)$. If $\Delta p \approx 10 \, Pa$,$v \approx 300 \, m/s$,$\rho \approx 1 \, kg/m^3$,and $f \approx 1000 \, Hz$,then $s$ will be of the order of (take multiplicative constant to be $1$).

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