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Chapter 29: Problem 3

Is there displacement current in an electromagnetic wave? Is there ordinary conduction current?

Short Answer

Expert verified
Yes, there is displacement current in an electromagnetic wave due to the time-varying electric field. However, there is no conduction current, because conduction current requires the presence of free charges which are not present in an electromagnetic wave in free space.

Step by step solution

01

Understand displacement current

Displacement current is a concept introduced by Maxwell that accounts for the conservation of electric charge in situations where there is a changing electric field, such as in a capacitor. It arises because of the time-varying electric flux and can be present even in regions of space where there are no free charges to carry a conduction current.
02

Apply concept to electromagnetic wave

In an electromagnetic wave such as light, the electric and magnetic fields vary sinusoidally and are perpendicular to each other. Because the electric field is changing, there will be displacement current associated with it. Therefore, yes, there is displacement current in an electromagnetic wave.
03

Understand conduction current

Conduction current refers to the flow of free charge carriers like electrons. In a good conductor like a metal wire, an imposed electric field can cause these free charges to drift, creating a conduction current.
04

Apply concept to electromagnetic wave

In an electromagnetic wave, especially in free space or in any region where there are no free charges, there can be no conduction current. Hence there is no ordinary conduction current in an electromagnetic wave.

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Most popular questions from this chapter

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