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प्रश्न
A type of electromagnetic wave has a wavelength of 50 Å. Name the wave and state one use of this type of wave.
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उत्तर
X-rays. These are used for determining fracture of bones, hidden objects in customs at Airports.
संबंधित प्रश्न
Define amplitude 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 does not change.
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 bulb horn ? Name the principle on which a bulb horn works.
What is a stethoscope ? Name the principle on which a stethoscope works.
Mention two properties of a wave, one property which varies and the other which remains constant when the wave passes from one medium to another.
(i) A man stands at a distance of 68 m from a cliff and fires a gun. After what time interval will he hear the echo, if the speed of sound in air is 340 ms−1?
(ii) If the man had been standing at a distance of 12 m from the cliff would he have heard a clear echo?
What is meant by an echo? Explain.
