ExamBro
ExamBro
CUET · PHYSICS · PYQ PAPER 2025

Which of the following has zero average value in a plane electromagnetic wave?
(A) Electric field
(B) Magnetic field
(C) Electric energy
(D) Magnetic energy
Choose the correct answer from the options given below:

  1. A (A) and (C) only
  2. B (B) and (D) only
  3. C (B) only
  4. D (A) and (B) only
Verified Solution

Answer & Solution

Correct Answer

(D) (A) and (B) only

Step-by-step Solution

Detailed explanation

The electric field \( \vec{E} \) and magnetic field \( \vec{B} \) in a plane electromagnetic wave oscillate sinusoidally, so their average values over a full cycle are zero. Electric energy \( U_E \propto E^2 \) and magnetic energy \( U_B \propto B^2 \). Since \( E^2 \) and…