Advertisements
Advertisements
प्रश्न
Advertisements
उत्तर
The sound heard after reflection from a rigid obstacle (such as cliff, a hillside, a wall of a building, edge of a forest etc.), is called an echo.
Conditions necessary for echo formation are:
1. The minimum distance between the source of sound and its reflector should be 17 m.
2. Reflected sound should reach the person atleast 0.1 second after the original sound is heard.
APPEARS IN
संबंधित प्रश्न
The following diagram shows three ways in which the string of an instrument can vibrate.
(a) which of the diagram shows the principal note?
(b) which has the frequency four times that of the first?
(c) what is the ratio of the frequency of the vibration in (i) and (ii)?
Name the principle on which a soundboard works.
What is a stethoscope ? Name the principle on which a stethoscope works.
What are infrasonic waves?
Write the approximate value of the speed of sound in air.
Write the approximate value of the speed of sound in iron.
A type of electromagnetic wave has a wavelength of 50 Å. Name the wave and state one use of this type of wave.
When a sound is made from a distance of 18 m, in front of a tall building, it is found to get repeated again. Which phenomenon is associated with this observation? Give a brief explanation of this phenomenon?
In what respect does waveforms of noise and a musical note differ. Draw diagrams to illustrate your answer.
A radio signal, sent towards the surface of the moon, is received in 2.5 seconds. If the speed of the radio waves is 3 × 108 ms−1, find the distance of the moon from the earth.
