Two instruments having stretched strings are being played in unison . When the tension in one of the instruments is increases by ` 1% , 3` beats are produced in ` 2 s`. The initial frequency of vibration of each wire is

Options

A. `600 Hz`
B. `300 Hz`
C. `200 Hz`
D. `150 Hz`

Answer

B

Explanation

` v prop sqrt(T) , v' prop sqrt (T + (1)/(100)T)`
`(v')/(v) = ( 1 + 1/ 100)^(1//2) = 1 + 1/200`
or ` (v' - v)/(v) = (1)/(200) or (3)/(2 v) = ( 1)/(200) or v = 300 Hz`