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Conditions for hearing echo - class-IX
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An echo of the sound produced can be heard only if it reaches our ear after -
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A
1 / 10th of a second
💡 Explanation:
An echo is the repetition of sound that results as a reflection from a surface. An echo of the sound produced can be heard only if it reaches our ear after 1 / 10th of a second. This is due to the persistence of sound.