Question

An electromagnetic wave is propagating along the +z axis. The electric and the magnetic fields, associated with this wave, can be represented by,

• A. $[\overrightarrow{E}=E_0\hat{i},\overrightarrow{B}=B_0\hat{k}]$
• B. $[\overrightarrow{E}=E_0\hat{i},\overrightarrow{B}=B_0\hat{j}]$
• C. $[\overrightarrow{E}=E_0\hat{k},\overrightarrow{B}=B_0\hat{j}]$
• D. $[\overrightarrow{E}=E_0\hat{j},\overrightarrow{B}=B_0\hat{i}]$

Answer 1

The correct option is B $[\overrightarrow{E}=E_0\hat{i},\overrightarrow{B}=B_0\hat{j}]$

In an electromagnetic wave,$\overrightarrow{E},\overrightarrow{B}$ and direction of propagation of wave are mutually perpendicular.
Also, $\overrightarrow{E}\times \overrightarrow{B}$ gives the direction of propagation of wave.

It is given that the wave is propagating along the +z axis.

So the electric and magnetic fields associated with given wave can be
$\overrightarrow{E}=E_0\hat{i}$ and $\overrightarrow{B}=B_0\hat{j}(\because \hat{i}\times \hat{j}=\hat{k})$

Hence, $\left(B\right)$ is the correct answer.