Question

A plane electromagnetic wave of frequency 25 GHz is propagating in vacuum along the z-direction. At a particular point in space and time, the magnetic field is given by $\vec{B}=5\times10^{-8}\,\hat{j}\,T$. The corresponding electric field $\vec{E}$ is (speed of light $c = 3 \times 10^8\, ms^{-1}$)

• A. $-1.66 \times 10^{-16}\,\hat{i}\,V /m$
• B. $1.66 \times 10^{-16}\,\hat{i}\,V /m$
• C. $-15\,\hat{i}\,V /m$
• D. $15\,\hat{i}\,V /m$

Answer 1

Answer: (D)

$E=\vec{B}\times\vec{V}$
$=\left(5\times10^{-8}\hat{j}\right)\times\left(3\times10^{8}\hat{k}\right)$
$=15\,\hat{i}\,V / m$