Saved Bookmarks
| 1. |
In a plane Electromagnetic wave the electric field oscillates sinusoidally at a frequency of 2.0 X 10^(10) Hz & amplitude 48 Vm^(-1). show that the average energy density of the electric field (vec(E )), is equal to average energy density of the magnetic field (vec(B)) |
|
Answer» Solution :Average energy magnetic field `vec(E )` `U_(E ) "" (1)/(2)CDOT epsilon_(0) E^(2) ` Average energy density of electric field `vec(B)` `U_(E ) = (1)/(2 mu_(0)) cdot B^(2)` But E = CB & `C^(2) = (1)/(mu_(0)epsilon_(0))` `U_(E ) = (1)/(2) cdot epsilon_(0) E^(2)= (1)/(2) cdot epsilon_(0)(CB)^(2)` `U_(E )= (1)/(2) cdot epsilon_(0) (1)/(mu_(0)epsilon_(0)) B^(2) = (1)/(mu_(0) epsilon_(0)) B^(2) = U_(B)` `THEREFORE U_(E ) = U_(B)` |
|