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To hear a clear echo, the minimum distance should be
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- 165 feet
- 165 meter
- 16.5 feet
- 16.5 meter
Correct Option: D
to hear a clear echo, the minimum distance should be 16.5 metre.
To hear an echo, time = 1/10 s
Velocity of sound (in air) = 330 ms -1
Time = 2d / Velocity of sound in air
⇒ 1/10 = 2d/330
∴ d = 16.5 metre.
