The nature of sound waves in gases is

On a windless day,sound emanates isotropically from a point source. Rays of the sound waves emanated from a point source placed close to the ground are shown in the figure. Consider horizontal wind towards the left blowing with constant velocity,which is uniform everywhere. In the following figures,rays of sound waves in the presence of the wind are shown. Which one is the most correct representation?

What is the ratio of the speed of sound in nitrogen gas to that in helium gas at the same temperature of $300 \, K$?

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

What is the velocity of a wave in a monoatomic gas having a pressure of $1 \, kPa$ and a density of $2.6 \, kg/m^3$?

$v_1$ 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