Question

Sound waves are not transmitted through to a long distance because :

• A. they are absorbed by the atmosphere
• B. they have constant frequency
• C. the height of antenna required should be very high
• D. velocity of sound waves is very less

Answer 1

The correct option is A they are absorbed by the atmosphere

There are several factors which affect the propagation of sound. These are geometric spreading, atmospheric effect and surface effects. There are two mechanisms by which acoustic energy is absorbed by the atmosphere. These are molecular relaxation and viscosity effects. The amount of absorption depends on the temperature and humidity of the atmosphere.
Note: Under normal circumstances atmospheric absorption can be neglected except where long distances or very high frequencies are involved.