Advertisements
Advertisements
प्रश्न
What is a megaphone ? Name the principle on which a megaphone works.
उत्तर
A megaphone is a large cone-shaped device used for amplifying and directing the voice of a person who speaks into it. A megaphone works on the principle of multiple reflections of sound. It is used for addressing a small gathering of people.
APPEARS IN
संबंधित प्रश्न
Displacement distance graph of two sound waves A and B, travelling in a medium, are as shown in the diagram below.
Study the two sound waves and compare their:
1) Amplitudes
2) Wavelengths
State two factors on which the speed of a wave travelling in a medium depends.
What do you mean by reflection of sound? State one condition for the reflection of a sound wave. Name a device in which reflection of sound wave is used.
Write the approximate value of the speed of sound in air.
What are fishing boats?
Why is an echo not heard when the distance between the source of sound and reflection body is less than 10 m?
Match the following:
| 1. | Stethoscope | a. | Repeated reflections |
| 2. | Echogram | b. | Multiple reflections |
| 3. | SONAR | c. | Ultrasonic waves |
| 4. | Reverberation | d. | Speed of underwater objects |
