Question

Assertation(A): The velocity of sound in air increases due to the presence of moisture in it:

Reason(R): The presence of moisture in air lowers the density of air.

• A. A and R are true and R is the correct explanation of A.
• B. A and R true, but R is not the correct explanation of A.
• C. A is true but R is false.
• D. Both A and R are false.

Answer 1

The correct option is A

A and R are true and R is the correct explanation of A.

Correct option is A: A and R are true and R is the correct explanation of A.

Explanation:

1. Relation between velocity and density, $v=\sqrt{\frac{\gamma P}{\rho }}$ (where $\rho$ is density and $P$ is pressure.)
2. $v\propto \frac{1}{\sqrt{\rho }}$ ( velocity is inversely proportional to root mean square of density.)
3. Moisture lowers the density of air, and hence, the velocity increases.
4. Hence, assertation is true and reason is correct explanation of assertation.