Let `n_(1) and n_(2)` be the two slightly different frequencies of two sound waves. The time interval between a waxing and the immediate next waning is

Options

A. `(1)/(n_(1) - n_(2))`
B. `(2)/(n_(1) - n_(2))`
C. `(n_(1) n_(2))/(2)`
D. `(1)/(2(n_(1) - n_(2)))`

Answer

D

Explanation

In this case beats are produced
Beat frequency = No. of beats/ sec `= [n_(1) - n_(2)]`
Period of beats = Time interval between two consecutive maxima or minima of sound or period of waxing or period of waning `= (1)/(n_(1) - n_(2))`

`:.` The time interval between a waxing and waning is `(1)/(2(n_(1) -n_(2)))`