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प्रश्न
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उत्तर
A simple method for finding the velocity of sound is echo or open air method.
For example: A person stands at a known distance (d m) from a cliff and fires a pistol and simultaneously starts the stop watch. He stops the stop-watch as soon as he hears the echo. The distance traveled by sound during this time (t seconds) is twice the distance (2d m). The velocity (v) of sound is then calculated as under:
Velocity of sound= `"distance travelled"/" time taken" = (2"d")/"t"`
By repeating the experiment two or three times, the average velocity of sound can be calculated.
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संबंधित प्रश्न
The 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:
- Amplitudes
- Wavelengths
Explain how the principle of echo is used by
The bat during its flight at
Why will an echo not be heard when the distance between the source of the sound and the reflecting surface is 10 m?
Name the type of waves that are used for sound ranging. Why are radio waves not audible to us?
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?
Draw a diagram representing a wave of amplitude 4 cm and wavelength 2 m. If the frequency of the wave is 150 Hz, calculate its velocity.
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.
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 |
