the fundamental frequency of a sonometer wire of length is `f_(0)`.A bridge is now introduced at a distance of `Deltal`from the centre of the wire `(Deltal lt lt l )`. The number of beats heard if their fundamental mode are

Options

A. `(8f_(0)Deltal)/(l)`
B. `(f_(0)Delta l)/(l)`
C. `(2f_(0)Deltal)/(l)`
D. `(4f_0 Delta l)/(l)`

Answer

A

Explanation

`f_0=(1)/(2L)sqrt((T)/(mu)), f=(1)/(2L)sqrt((T)/(mu))`
`implies Delta=2f(Delta)/(l')`
`implies Deltaf=2f_0(2Delta)/(l//2)=8((f_0Delta))/(l)`