Chapter 26, Problem 33A

Why is an echo weaker than the original sound?

To determine

The echo is weaker than the original sound; the reason behind the fact is to be explained.

Answer to Problem 33A

Echo is the secondary sound which generated due to the reflections of original sound from surrounded boundaries or objects resulting in weaker echo.

Explanation of Solution

Introduction: It involves the concept of reflection and absorption of sound waves by surrounding objects and understands the difference between original sound and secondary sound.

An echo is a form of sound waves that have been generated due to back and forth a reflection of the sound wave from the surrounding surface such as a room divider at the other end of a room. Upon striking the surface some part of the original sound waves is absorbed by the wall and rest of the part is reflected. This absorption takes place due to resonance in the frequency of the sound wave and the natural frequency of vibrations of molecules of the wall. This results in the absorption of some frequency components of the original sound waves, thus making echo weaker than the original sound.

Conclusion: Absorption of some frequency components of the original sound wave by the vibrating molecules of the wall makes the echo weaker than the original sound.