Q. A cell of internal resistance $3\ ohm$ and $emf\ 10\ volt$ is connected to a uniform wire of length $500\ cm$ and resistance $3\ ohm.$ The potential gradient in the wire is
A) $30\ mV/cm$
B) $10\ mV/cm$
C) $20\ mV/m$
D) $4\ mV/cm$
Explanation
(b) Potential gradient $= \ \frac{e.R}{(R + r).L} = \frac{10 \times 3}{(3 + 3) \times 5}$
$= 1V/m = 10\ mV/cm$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.