Question

Choose the correct answer from alternatives given.
If $\overrightarrow{E}$ and $\overrightarrow{B}$ represent electric and magnetic field vectors of an electromagnetic wave, the direction of propagation of the wave is along

• A. $\overrightarrow{B}\times \overrightarrow{E}$
• B. $\overrightarrow{B}$
• C. $\overrightarrow{E}$
• D. $\overrightarrow{E}\times \overrightarrow{B}$

Answer 1

The correct option is D $\overrightarrow{E}\times \overrightarrow{B}$

Electromagnet waves have electric field as well as magnetic field which are perpendicular to each other and the electromagnetic waves propagate in a direction which is perpendicular to both the fields.

Thus the propagation vector of EM waves $\overrightarrow{k}=\overrightarrow{E}\times \overrightarrow{B}$