Question

In a plane electromagnetic wave, the electric field oscillates sinusoidally at a frequency of $2.5\times 10^{10} \, Hz$ and amplitude $480 \, V \, m^{- 1}$ . The amplitude of the oscillating magnetic field will be

• A. $\text{1.52}\times 10^{- 8} \, Wbm^{- 2}$
• B. $\text{1.52}\times 10^{- 7} \, Wbm^{- 2}$
• C. $\text{1.6}\times 10^{- 6} \, Wbm^{- 2}$
• D. $\text{1.6}\times 10^{- 7} \, Wbm^{- 2}$

Answer 1

Answer: (C)

If $c$ is the speed of light or electromagnetic wave then the amplitude of electric and magnetic fields are related as,
$B_{0}=\frac{E_{0}}{c}$
$B_{0}=\frac{480}{3 \times 1 0^{8}}=1.6\times 10^{- 6} \, Wb \, m^{- 2}$