Question

Oscillating magnetic field in a plane, electromagnetic wave is given by
$\vec{B}_{y}=4 \times 10^{-6} \sin \left[9 \times 10^{9} t-30 x\right]$ tesla.
Expression for oscillating electric field (in $N\, C ^{-1}$ ) will be

• A. $\vec{E}_{z}=600 \sin \left[9 \times 10^{9} t-30 x\right] \hat{k}$
• B. $\vec{E}_{z}=-600 \sin \left[9 \times 10^{9} t-30 x\right] \hat{k}$
• C. $\vec{E}_{z}=1200 \sin \left[9 \times 10^{9} t-30 x\right] \hat{k}$
• D. $\vec{E}_{z}=-1200 \sin \left[9 \times 10^{9} t-30 x\right] \hat{k}$

Answer 1

Answer: (D)

$\frac{E_{0}}{B_{0}}=c$
$\Rightarrow E_{0}=c B_{0}=3 \times 10^{8} \times 4 \times 10^{-6}=1200\, N\, C ^{-1}$
$\Rightarrow \vec{E}_{z} \equiv-1200 \sin \left[9 \times 10^{9} t-30 x\right] \hat{k} \,N\, C ^{-1}$