The prong of an electrically operated tuning fork is connected to a long string of `mu=1 kg//m` and tension 25 N, the maximum velocity of the prong is `1 cm//s`, then the average power needed to drive the prong is

Options

A. `5xx10^(-4) W`
B. `2.5xx10^(-4)W`
C. `1xx10^(-4)W`
D. `10^(-3)W`

Answer

b

Explanation

Wave velocity: `v=sqrt((F)/(mu))=sqrt((25)/(1))=5 m//s`
Average power: `p_(av)=(1)/(2)muv(omegaA)^(2)`
`=(1)/(2)muv(v_(p-max))^(2)=(1)/(2)xx1xx5(1xx10^(-2))^(2)`
`=2.5xx10^(-4) W`