Question

In a plane electromagnetic wave, the electric field of amplitude \( 1 \text{ V m}^{-1} \) varies with time in free space. The average energy density of magnetic field is (in \( \text{Jm}^{-3} \))

• A. \( 8.86 \times 10^{-12} \)
• B. \( 4.43 \times 10^{-12} \)
• C. \( 17.72 \times 10^{-12} \)
• D. \( 2.21 \times 10^{-12} \)
• E. \( 1.11 \times 10^{-12} \)

Hint:

Always remember that for any EM wave in a vacuum, the average energy stored in the electric field is exactly equal to the average energy stored in the magnetic field 120].

Answer 1

The Correct Option is D