At normal temperature, for an echo to be heard the reflecting surface should be at a minimum distance of …………m.
(A) 34.4
(B) 17.2
(C) 10
(D) 20
1 Answers
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What do you mean by an echo?
An echo is the repetition of the original sound because of reflection from some rigid surface at a distance from the source of sound.
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The minimum age which should be considered to measure literacy rate ………………
Correct option is A) 7 years
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The total surface area of solid cylinder is `231 cm^(2)` and its curved surface area is `(2)/(3)` of the total surface area. Find the volume of the cy
Correct Answer - `269.5 cm^(3)`
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The final temperature of a mixture of 100g of water at 30°C temperature and 100g of water at 60°C temperature is ………………………
Correct option is A) 45° C
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We cannot hear an echo at every place. Give reason.
1. Echo of sound depends upon the temperature of the surrounding and distance between source and reflecting surface. 2. To hear a distinct echo at 22 °C, the minimum distance required between...
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A man shouts loudly close to a high wall. He hears an echo. If the man is at 40 m from the wall, how long after the shout will the echo be heard?
Given: s = 40m, v = 330 m/s To Find: time (t) Formula: Time = distance \(\frac{distance}{speed}\) Calculation: The distance travelled by the sound wave = 2 × distance from man to wall. = 2 × 40...
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Far point of a person is 5 m. In order to have normal vision what kind of spectacles should he use ?
A) Concave lens with focal length 5 m
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The point at which principal axis is perpendicular to the reflecting surface of concave mirror is called
Correct option is C) pole
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Echo is a reflected sound, reaches our ear, after direct sound in
B) more than 0.1s
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The temperature `30.98^(@)C` is called critical temperature `(T_(C))` of carbon dioxide. The critical temperature is the
Correct Answer - (d)
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