The electric field of a plane electromagnetic wave varies with time of amplitude 2 `Vm^(-1)` propagating along z-axis. The average energy density of the magnetic field is (in `Jm^(-3)`)

Options

A. `13.29 xx 10^(-12)`
B. `8.86 xx 10^(-12)`
C. `17.72 xx 10^(-12)`
D. `4.43 xx 10^(-12)`

Answer

B

Explanation

`U = (1)/(2) xx (1)/(2) epsilon_(0)E^(2) = (1)/(2) xx (1)/(2) xx 8.85 xx 10^(-12) xx (2)^(2)`
`= 8.85 xx 10^(-12) Jm^(-3)`