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. `sqrtc:1`

Answer

c

Explanation

Intensity of em wave, `I=u_(av)c`
In terms of electric field, `(u_(av))=1/2in_0 E_0^2` , In terms of magnetic field, `u_(av)=1/2 (B_0^2)/(mu_0)`
Now `(u_(av))_("electric field")=1/2in_0 E_0^2=1/2in_0(cB_0)^2=1/2 in_0xx1/(mu_0in_0) B_0^2=1/2 (B_0^2)/(mu_0)= (u_(av))_("due to magnetic field")`
Thus the energy in em wave is divided equally between electric field vector and magnetic field vector.
Therefore, the ratio of contributions by the electric field and magnetic field components to the intensity
of em wave is 1:1.