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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
Define wavelength term in relation to a wave.
A wave passes from one medium to another medium. Mention one property of the wave out of speed, frequency or wavelength which changes.
State the use of echo by a bat, dolphin and fisherman.
What is the shape of a soundboard kept behind the speaker on the stage of a big hall ?
What is a stethoscope ? Name the principle on which a stethoscope works.
Draw a labelled diagram to show the multiple reflections of sound in a part of the stethoscope tube.
What are fishing boats?
A sound wavelength of 0.332 m has a time period of 10−3 s. If the time period is decreased to 10−4 s, calculate the wavelength and frequency of the new wave.
Explain why, the ceilings of concert halls are curved.
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 |
