During the propagation of electromagnetic waves in a medium: (a) Electric energy density is double of the magnetic energy density. (b) Electric energy density is half of the magnetic energy density. (c) Electric energy density is equal to the magnetic energy density. (d) Both electric and magnetic energy of densities are zero.

Answer: (c). In a medium E = vB with v = 1/√(με). 1/2ε E² = 1/2ε v² B² = (B²)/(2μ) So electric and magnetic energy densities are equal; the answer is (c).

During the propagation of electromagnetic waves in a medium: | JEE Main 2014

Q33JEE Main 2014Easy

Energy Density & Intensity

During the propagation of electromagnetic waves in a medium:

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Answer: (c)

In a medium $E = vB$ with $v = 1/\sqrt{\mu\varepsilon}$ .
$\tfrac{1}{2}\varepsilon E^2 = \tfrac{1}{2}\varepsilon v^2 B^2 = \dfrac{B^2}{2\mu}$
So electric and magnetic energy densities are equal; the answer is (c).

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