(a) Consider a medium composed of N one-dimensional, undamped Lorentz oscillators per unit volume. Show by explicit calculation that the time average of

is equal to the time average of the sum of the electric, kinetic, and potential energy densities of the medium.
(b) Consider a Drude medium with momentum relaxation time τ . Show by explicit calculation that the time average of

is equal to the time average of the rate at which the fields do work on the charges in a unit volume of the medium.

Transcribed Image Text:

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