Question

For hearing an echo, the minimum distance between the source of sound and reflecting body should be:

Options

• 12 m

• 24 m

• 17 m

• 51 m

Answer 1

17 m

Explanation:

The reflected sound must return after the persistence of hearing, which is about 0.1 s.

Minimum distance (d) = \[\frac{vt}{2}\]

= \[\frac{332 \times 0.1}{2}\]

= 16.6 m

= 17 m (Appox.)