Question

Sound waves in air are always longitudinal because :

• A. of the inherent characteristics of sound waves in air
• B. air does not have a modulus of rigidity.
• C. air is a mixture of several gases.
• D. density of air is very small.

Answer 1

The correct option is B air does not have a modulus of rigidity.

Longitudinal waves travel in an elastic medium in form of compression and rarefaction which changes its volume,elasticity and pressure.

Since air is completely elastic medium, that is, it does not have a modulus of rigidity, therefore sound waves in air are longitudinal.