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

Average energy by electric field `E_(0)` is `U_(av)`
`U_(av) = (1)/(2) epsilon_(0)E_(0)^(2)`
But `E_(0) = c B_(0)`
`(U_(a v))_("electric field") = (1)/(2) epsilon_(0)(c B_(0))^(2) = (1)/(2) epsilon_(0)c^(2)B_(0)^(2)`
`= (1)/(2)epsilon_(0)(1)/(mu_(0) epsilon_(0))(B_(0))^(2) because c^(2) = (1)/(mu_(0)epsilon_(0))`
`(U_(av))_("electric field") = (1)/(2 mu_(0))B_(0)^(2)(U_(av))_("(magnetic field)")`
Ratio `= ((U_(av))_("electric field"))/((U_(av))_("magnetic field"))`
`= (1)/(2)`, i.e., `1:1`