The wavelength of ultrasonic waves in air is of the order of

If the pressure, temperature, and density of an ideal gas are denoted by $p, T$ and $\rho$, respectively, the velocity of sound in the gas is

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: $A$ sound wave has higher speed in solids than gases.
Reason $R$: Gases have higher value of Bulk modulus than solids.
In the light of the above statements,choose the correct answer from the options given below:

$A$ man sets his watch by a whistle that is $2\, km$ away. How much will his watch be in error? (Speed of sound in air = $330\, m/s$)

Does an oscillating source always produce sound waves?

$A$ sound wave of frequency $v \text{ Hz}$ initially travels a distance of $1 \text{ km}$ in air. Then, it gets reflected into a water reservoir of depth $600 \text{ m}$. The frequency of the wave at the bottom of the reservoir is $(V_{\text{air}} = 340 \text{ m/s}, V_{\text{water}} = 1484 \text{ m/s})$