Question

ii) DC current flows in a metal piece of non-
uniform cross-section. Which of these
quantities remains constant along the
conductor: current, current density or
drift speed?​

Answer 1

Answer:

The answer is Current.

Explanation:

By definition,

• Current : Flow of charges through a conductor.
• Current Density ( J ∝ 1/A ) : The rate at which charge flows through a specific unit area.
• Drift Speed ( $V_{d}$ ∝ 1/A ): The speed at which charged particles move constantly in random direction withing the conductor.

Conclusion:  As per above definitions, current density and drift speed both depend on the area of the conductor.

So, the current is the only quality which will remain constant during DC flow in a conductor having non-uniform cross-section.