Question

Jonathan placed a surface before a
sound source to hear a distinct echo. The
minimum distance of a reflecting surface
should be: (Speed of sound in air = 344 m/s)
17.2 m
O 34.4 m
9.8 m
3.40 m​

Answer 1

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Answer 2

Explanation:

The total distance covered by the sound from the point of generation to the reflecting surface and back should be at least (344 m/s) × 0.1 s = 34.4 m. Thus, for hearing distinct echoes, the minimum distance of the obstacle from the source of sound must be half of this distance, that is, 17.2 m.