The length of two open organ pipes are `l` and `(l+deltal)` respectively. Neglecting end correction, the frequency of beats between them will b approximately.

Options

A. `(v)/(2 l)`
B. `(v)/(4 l)`
C. `(v Delta l)/(2 l^(2))`
D. `(v Delta l)/(l)`

Answer

C

Explanation

Beat frequyency`= (v)/(2l) - (v)/(2(l+Delta l))`
`= (v)/(2l)[1-(1)/((1+Delta l//l))]`
`= (v)/(2l)[1-(1+(Delta l)/(L))^(-1)] = (v Delta l)/(2 l^(2)`