Question 56 of 165

If $\vec{E}$ and $\vec{K}$ represent electric field and propagation vectors of the EM waves in vacuum, then magnetic field vector is given by:
($\omega -$ angular frequency)

A$\dfrac{1}{\omega }\left(\vec{K}\times \vec{E}\right)$B$\omega \left(\vec{E}\times \vec{K}\right)$C$\omega \left(\vec{K}\times \vec{E}\right)$D$\vec{K}\times \vec{E}$

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Answer: (A) $\dfrac{1}{\omega }\left(\vec{K}\times \vec{E}\right)$

As we know, direction of electromagnetic wave will be in the direction of the vector $\vec{E}\times \vec{B}$.

Magnitude of $B=\dfrac{E}{c}=\dfrac{K}{\omega }E$
$\Rightarrow \vec{B}=\dfrac{1}{\omega }\left(\vec{K}\times \vec{E}\right)$

JEE Main Physics practice question on Electromagnetic Waves (Electromagnetic Waves and Maxwell's equations), with the answer and a step-by-step solution. Scan a question from your own book or paper to get a whiteboard video.