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प्रश्न
A boy stands 66.4 m in front of a high wall and then blows a whistle. Calculate the time interval when he hears an echo. (Speed of sound = 332m/s).
उत्तर
Given: d = 66.4 m
v = 332 m/s
For an echo the distance travelled by the sound is 2d
Time = `(2"d")/"v"=(2xx66.4)/332` = 0.45 second.
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