What should be minimum distance between listener and reflecting surfac

1.	What should be minimum distance between listener and reflecting surface ?
Answer» 28m 18M 19m `16.6m` Solution :Is same sound is heard after time `t ge (1)/(10)` s DUE to reflection then it is called an ECHO (because sensation of hearing LASTS for `(1)/(10)s` in human EARS). Thus, `t _(min) = (1)/(10) s=0.1 s` Now, when sound is reflected from reflector at distance x from its source and echo is heard at the end of t time. `v = (2x)/(t) implies x = (vt)(2) implies x_(min) = (v)/(2)xx t _(min)` `therefore x_(min) = (332)/(2) xx 0.1 = 16.6 m`

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