In an E.M. wave average energy density is associated with

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8.Electromagnetic waves

easy

In an $E.M.$ wave the average energy density is associated with

A

electric field only

B

magnetic field only

C

electric and magnetic fields equally

D

average energy density is zero

Solution

Energy density due to electric field $=\frac{1}{2} \epsilon E^{2}$

Energy density due to magnetic field $=\frac{1}{2} \frac{B^{2}}{\mu}$

since $\frac{E}{B}=c=\frac{1}{\sqrt{\epsilon \mu}}$

Energy density is equally contributed to by electric and magnetic fields.

Standard 12

Physics

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