Question

Which of the following is incorrect about a plane electromagnetic wave?

• A. The electric field and magnetic field have equal average values
• B. The electric energy and the magnetic energy have equal average values
• C. The electric field and magnetic field both oscillate in same phase
• D. The electric field and magnetic field oscillate in opposite phase

Answer 1

Answer: (D)

$\vec{E}$ and $\vec{B}$ are in the same phase but oscillate in different planes which are perpendicular to each other.