Question

A steady current is flowing in a metallic conductor of non-uniform cross section. The physical quantity which remains constant is

• A. Electricity current density
• B. Drift velocity
• C. Electricity current density and drift velocity
• D. Electric current

Hint:

In any steady state situation, the total electric current remains constant, even if the current density varies across the conductor.

Answer 1

The Correct Option is D

In a conductor with non-uniform cross-section, the electric current remains constant at every point along the length of the conductor. This is a consequence of the law of conservation of charge. The current \( I \) is related to the current density \( J \) and the area \( A \) by: \[ I = J A \] Since the current is constant, the product of the current density and the area remains constant, but the current density itself can vary with the cross-sectional area. Thus, the electric current remains constant.