# An electromagnetic wave in vacuum has the electric and magnetic fields

Question:

An electromagnetic wave in vacuum has the electric and magnetic fields $\overrightarrow{\mathrm{E}}$ and $\overrightarrow{\mathrm{B}}$, which are always perpendicular to each other. The direction of polarization is given by $\overrightarrow{\mathrm{X}}$ and that ofwave propagation by $\vec{k}$. Then

1. $\overrightarrow{\mathrm{X}} \| \overrightarrow{\mathrm{B}}$ and $\overrightarrow{\mathrm{k}} \| \overrightarrow{\mathrm{E}} \times \overrightarrow{\mathrm{B}}$

2. $\overrightarrow{\mathrm{X}} \| \overrightarrow{\mathrm{E}}$ and $\overrightarrow{\mathrm{k}} \| \overrightarrow{\mathrm{B}} \times \overrightarrow{\mathrm{E}}$

3. $\overrightarrow{\mathrm{X}} \| \overrightarrow{\mathrm{B}}$ and $\overrightarrow{\mathrm{k}} \| \overrightarrow{\mathrm{B}} \times \overrightarrow{\mathrm{E}}$

4. $\overrightarrow{\mathrm{X}} \| \overrightarrow{\mathrm{E}}$ and $\overrightarrow{\mathrm{k}} \| \overrightarrow{\mathrm{E}} \times \overrightarrow{\mathrm{B}}$

Correct Option: , 4

Solution:

Factual Question