Question

In an electromagnetic wave

• A. power is transmitted along the magnetic field
• B. power is transmitted along the electric field
• C. power is equally transferred along the electric and magnetic fields
• D. power is transmitted in a direction perpendicular to both the fields

Answer 1

Answer: (D)

For electromagnetic waves $\vec{ E }$ and $\vec{ B }$ are always perpendicular to each other and perpendicular to the direction of propagation. The direction of propagation is the direction of $\vec{E} \times \vec{B}$.
The direction of propagation of the wave is the direction of propagation of its energy and power.