A plane electromagnetic wave of frequency 30 MHz travels in free space along the x-direction. At a particular point in space and time $\vec E = 6.3\hat j\, V/m$. The $\vec B$ at this point would be:

$2.1 × 10^{-8}\hat k\, T$

The correct answer is Option (1) → $2.1 × 10^{-8}\hat k\, T$

Electric field ($\vec E$) and Magnetic field ($\vec B$) is related by -

$C=\frac{\vec E}{\vec B}$ where $[C=3×10^8m/s]$

$\vec B=\frac{6.3}{3×10^8}$

$=2.1 × 10^{-8}\hat k\, T$