Question

Given, a current carrying wire of non-uniform cross-section, which of the following is constant throughout the length of the wire?

• A. Current only
• B. Current, electric field, and drift speed
• C. Drift speed
• D. Current and drift speed

Hint:

The current remains constant throughout a conductor even if its cross-sectional area changes, as charge conservation must hold. However, the electric field and drift speed vary with the area.

Answer 1

The Correct Option is A

In a current-carrying wire, the current is constant throughout the length of the wire, even if the cross-section of the wire changes. This is due to the conservation of charge, which ensures that the same amount of charge flows through any cross-sectional area of the wire per unit of time. The electric field and drift speed depend on the cross-sectional area of the wire and may vary along its length if the wire has a non-uniform cross-section. Thus, only the current remains constant throughout the length of the wire.