Which of the following is not a transverse wave?

Which of the following cannot be polarised?

The speed of sound in air at temperature $T$ and pressure $p$ is $v$. When the temperature is increased to $2 T$ and the pressure is reduced to $\frac{p}{2}$, then the speed is changed to

Calculate the temperature at which the speed of sound will be two times its value at $0\,^oC$. (in $,K$)

Sound waves in air are

Sound waves travel at $350 \ m/s$ through warm air and at $3500 \ m/s$ through brass. The wavelength of a $700 \ Hz$ acoustic wave as it enters brass from warm air: