The ratio of contributions made by the eletric field and magnetic field components to the intensity of an `EM` wave is.

Options

A. `c : 1`
B. `c^(2) :1`
C. `1 : 1`
D. `sqrt(c) :1`

Answer

C

Explanation

Intensity of electromagnetic wave, `I = U_(av) c`
In terms of electric field, `U_(av) = (1)/(2) epsilon_(0)E_(0)^(2)`
In terms of magnetic field, `U_(av) = (1)/(2) (B_(0)^(2))/(mu_(0))`
Now `U_(av)` (due to the electric field) `=(1)/(2) epsilon_(0) E_(0)^(2)`
`= (1)/(2) epsilon_(0) (cB_(0))^(2) = (1)/(2) epsilon_(0) xx (1)/(mu_(0)epsilon_(0)) B_(0)^(2) ( :' (E_(0))/(B_(0)) = c)`
`=(1)/(2) (B_(0)^(2))/(mu_(0)) = U_(av)` (due to magnetic field)
Therefore, the ratio of contributions by the electric field and magnetic field components to the intensity of electromagnetic wave is 1:1.