Q. In a potentiometer circuit there is a cell of e.m.f. $2\ volt,$ a resistance of $5\ ohm$ and a wire of uniform thickness of length 1000 $cm$ and resistance $15\ ohm.$ The potential gradient in the wire is
A) $\frac{1}{500}V/cm$
B) $\frac{3}{2000}V/cm$
C) $\frac{3}{5000}V/cm$
D) $\frac{1}{1000}V/cm$
Explanation
(b) Potential gradient $x = \frac{V}{L} = \frac{iR}{L}$
$\Rightarrow x = \frac{2}{(15 + 5)} \times \frac{15}{10} = \frac{3}{2000}\ volt/cm$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.