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

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 $\,ms^{-1}$)

Two sound sources produce waves at a certain temperature in air with wavelengths $50 \text{ cm}$ and $50.5 \text{ cm}$ respectively. The frequencies of the sources differ by $6 \text{ Hz}$. The velocity of sound in air at the same temperature is (in $\text{ m/s}$)

Write Newton's equation for the speed of a sound wave in air.

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

The minimum distance of the reflector surface from the source to hear the echo of sound is ..... $m$.