Same chapter3 marksDifficulty: Medium
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3 marksDifficulty: Medium
What is the minimum distance from a reflecting surface at which an echo can be heard distinctly, if the speed of sound is 340 m s−1 and the ear can separate two sounds 0.1 s apart?
Original Khojo Papers practice question — not from a past board paper.
Answer
17 m
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
In 0.1 s sound travels 34 m, and that is the distance there and back, so the reflector must be at least 17 m away.
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