Electromagnetic Waves - Result Question 14
14. The electric and magnetic field of an electromagnetic wave are
[2007]
(a) in opposite phase and perpendicular to each other
(b) in opposite phase and parallel to each other
(c) in phase and perpendicular to each other
(d) in phase and parallel to each other.
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Answer:
Correct Answer: 14. (c)
Solution:
- (c) Variation in magnetic field causes electric field and vice-versa.
In electromagnetic waves, $\vec{E} \perp \vec{B}$. Both $\vec{E}$ and $\vec{B}$ are in the same phase.
In electromagnetic waves
$E=E_0 \sin (\omega t-k x)$
$B=B_0 \sin (\omega t-k x)$
The electromagnetic waves travel in the direction of $(\vec{E} \times \vec{B})$.
