Question

A plane electromagnetic wave of frequency $20\, MHz$ travels through a space along x- direction. If the electric field vector at a certain point in space is $6\, V$ $m^{-1}$, what is the magnetic field vector at that point ?

• A. $2 \times 10^{-8} \, T$
• B. $\frac{1}{2} \times 10^{-8} \,T$
• C. $2T$
• D. $\frac{1}{2}$ T

Answer 1

Answer: (A)

$2 \times 10^{-8} \, T$

Answer 2

The magnetic field $B=\frac{E}{c}$ where $c=3 \times 10^{8} m / s$ $B=\frac{6}{3 \times 10^{8}}=2 \times 10^{-8} T$