The vector E and B of an electromagnetic wave in vacuum are - Vidyadip

MCQ

The vector $\vec E$ and $\vec B$ of an electromagnetic wave in vacuum are

A
along the same direction but of phase by $90^o$
B
along the same direction and in phase
✓
perpendicular to each other and in phase
D
perpendicular to each other and out of phase by $90^o$

✓

Answer

Correct option: C.

perpendicular to each other and in phase

c
$S_{a v}=\frac{1}{2} \varepsilon_{0} E_{0}^{2} c=\frac{P}{4 \pi R^{2}}$

$\therefore \mathrm{E}_{0}=\sqrt{\frac{\mathrm{P}}{2 \pi \mathrm{R}^{2} \varepsilon_{0} \mathrm{c}}}$

$=\sqrt{\frac{3}{2 \times 3.14 \times 100 \times 8.86 \times 10^{-12} \times 3 \times 10^{8}}}$

$=1.34 \mathrm{\,V} / \mathrm{m}$

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