Question

A plane electromagnetic wave travels in vacuum along $\hat{k}$ direction, where $\hat{i},\hat{j}$ and $\hat{k}$ are unit vectors along the $x,y$ and $z$ directions. The direction along which the electric and the magnetic field vectors point may be respectively

• A. $\hat{i}$ and $\hat{j}$
• B. $\hat{i}$ and $-\hat{j}$
• C. $\hat{j}$ and $\hat{i}$
• D. $\hat{k}$ and $\hat{i}$

Answer 1

The correct option is A $\hat{i}$ and $\hat{j}$

Electromagnetic wave is a transverse wave that means the electric and magnetic field associated to it will not only be perpendicular to each other but will also be perpendicular to the direction in which the wave travels.
So, if waves travel along $\hat{k}$ direction then the electric and the magnetic field will be along $\hat{i}$ and $\hat{j}$ directions.