Question

A steady current flow in a metallic conductor of non-uniform cross-section. The quantity/quantities remaining constant along the whole length of the conductor is/are

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

Answer 1

Answer: (D)

current only

Answer 2

When a steady current flows in a metallic conductor of non-uniform crosssection then the drift speed is $V _{ d }= I /$ neA and the electric field $E = I / pA$ $\Rightarrow V _{ d } \propto \frac{1}{ A }$ and $E \propto \frac{1}{ A }$ $\Rightarrow$ Only current remains constant. In a metallic conductor of non-uniform cross-section, only the current remains constant along the entire length of the conductor.