Q. The $V$-$i$ graphs $A$ and $B$ are drawn for two voltameters. Identify each graph
A) $A$ for water voltameter and $B$ for $Cu$ voltameter
B) $A$ for $Cu$ voltmeter and $B$ for water voltameter
C) Both $A$ and $B$ represents $Cu$ voltameter
D) None of these
Explanation
(a) $Cu$ voltameter with soluble electrodes obeys ohm’s law. In water voltameter, in the beginning when $V$ is small ($< 1.7\ volt$), very little current flows, the voltameter does not obey ohm’s law. As soon as $V$ exceeds $1.7\ volt$ (back e.m.f.) the current increases steadily according to ohm’s law
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.