Question

Describe any two applications of reflection of sound.

Answer 1

Application 1: Megaphone or speaking tube

• Whenever we call a person who is at a distance of around $100m$ away from us, we cup our hands and call out that person with the maximum sound that we can produce.
• Because of the hands, the sound energy is prevented from spreading in all directions.
• Similarly, people use horn-shaped metal tubes, which are commonly known as megaphones, while addressing a group of people in fairs or tourist spots or any such crowded places.
• The loudspeakers used at the public address also have horn-shaped openings.
• In all such devices, the spreading out of sound energy is prevented by successive reflections from the horn-shaped tubes.

Application 2: Ear trumpet or hearing aid

• People who face difficulty in hearing often use ear trumpets. It is shaped like a trumpet.
• The part of the ear trumpet which is narrow is kept in the ear hole of the person, whereas the wider end is towards the speaker.
• The sound waves that the wider end receives are reflected into the narrow end.
• This causes an increase in the intensity of sound energy, and hence the person with difficulty in hearing can hear clearly.