The **potential gradient** $K$ along a uniform potentiometer wire is defined as:
- Current per unit length
- Resistance per unit length
- Potential difference per unit length of the wire
- EMF per unit area
Show answer and solution
Correct answer: C. Potential difference per unit length of the wire
$K = V_{AB}/L$ — potential drop per unit length along the wire.
For a steady current and uniform wire, $K$ is constant and the potential at a point at distance $\ell$ from A is $V = K\ell$.