Question

The engineer of a train blows the train whistle as he approaches a crossing. A few moments later, he hears an echo from the whistle. The engineer hears the echo of the whistle because of

• A. reflection
• B. refraction
• C. constructive interference
• D. destructive interference

Hint:

An echo is the reflection of sound waves from a surface. It occurs when the reflected sound wave reaches the source after a short delay.

Answer 1

The Correct Option is A

An echo is heard when sound waves are reflected off a surface and return to the source. In this case, the engineer hears the echo of the whistle because the sound waves from the whistle are reflected by a surface (e.g., a building or a hill), and they return to the engineer. This is an example of reflection of sound waves.

Hence, the correct answer is (a).