JEE Main 2020 — Electromagnetic Waves Question with Solution

Polarization of EM Wave means Direction of Its electric Field

Electric field vector is along $\hat{k}$

So, unit electric filed vector, $\overrightarrow{E}=\hat{k}$ (Given)

Direction of wave,$\hat{c}=\frac{\hat{i}+\hat{j}}{\sqrt{2}}$  (Given)

$\hat{B}$  denotes unit magnetic field vector.

$\hat{B}=\hat{C} \times \hat{E}$

$\hat{B}=\frac{\hat{i}+\hat{j}}{\sqrt{2}}\times \hat{k}=\frac{\hat{i}-\hat{j}}{\sqrt{2}}$

General Form is $B=\left(B_0\hat{B}\right)\cos \left(\omega t-\hat{c}k\right)$

where $B_0$ is Magnitude of Magnetic Field

$So, B=B_0\frac{\hat{i}-\hat{j}}{\sqrt{2}}\cos \left(\omega t-k\frac{\hat{i}+\hat{j}}{\sqrt{2}}\right)$