Question

Which one of the following is a property of a monochromatic, plane electromagnetic wave in free space?

• A. Electric and magnetic fields have a phase difference of $\pi /2$
• B. The energy contribution of both electric and magnetic fields are equal
• C. The direction of propagation is in the direction of $\overline{B}\times \overline{E}$
• D. The pressure exerted by the wave is the product of its speed and energy density.

Answer 1

The correct option is B The energy contribution of both electric and magnetic fields are equal

The energy contribution of both electric and magnetic fields are equal, Energy density is written as $E=\frac{1}{2}{ϵ}_0{E}^2=\frac{B^2}{2{\mu }_0}$

And the direction of propagation of wave is written as $\hat{V}=\hat{E}\times \hat{B}$

Option B