An echo repeats two syllables. If the velocity of sound is 330 m/s. then the distance of reflecting surface is :

Options

A. 16.5 m
B. 33.0 m
C. 66 m
D. 99 m

Answer

C

Explanation

A man can speak 5 syllable in 1 sec.
`therefore ` time taken to speak disyllable = `(2)/(5) `sec
If d is the distance of reflector then .
` t = (2 d)/(v) `
`(2)/(5) = (2d)/(330)`
`rArr " " d = 66 m `
Hence the corret choice is (C).