Physics
The minimum distance between the source and the reflector in air, to hear an echo, is approximately:
- 10 m
- 17 m
- 34 m
- 50 m.
Sound
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Answer
17 m
Reason — To hear the echo distinctly, the minimum distance between the source of sound (or observer) and the reflector in air must be 17 m because if the distance is less than 17 m, the reflected sound will reach the ears before the original sound dies out (i.e., before 0.1 s) and so no echo will be heard.
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Related Questions
For an echo, the reflected sound must reach the person at least …………… after the original sound is heard.
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