Shown in the figure is a circular loop of radius `r` and resistance `R`. A varible magnetic field of induction `B=B_(0)e^(-t)` is established inside the coil. If the key `(K)` is closed, the electrical power devloped right after closing the switch is equal to

Options

A. `(B_(0)^(2)pi r^(2))/(R)`
B. `(B_(0)10r^(3))/(R)`
C. `(B_(0)^(2)pi^(2) r^(4)R)/(5)`
D. `(B_(0)^(2)pi^(2) r^(4))/(R)`

Answer

D