Q. Two voltameters, one of copper and another of silver, are joined in paralleled. When a total charge $q$ flows through the voltameters, equal amount of metals are deposited. If the electrochemical equivalents of copper and silver are $z_{1}\ and\ \ z_{2}$ respectively, the charge which flows through the silver voltameter is
A) $\frac{q}{1 + \frac{z_{1}}{z_{2}}}$
B) $\frac{q}{1 + \frac{z_{2}}{z_{1}}}$
C) $q\frac{z_{1}}{z_{2}}$
D) $q\ z_{2}/z_{1}\ \ $
Explanation
(b) We know $m = zq$
$\Rightarrow z \propto \frac{1}{q}$
$\therefore\ \frac{z_{2}}{z_{1}} = \frac{q_{1}}{q_{2}}$
Total charge $q = q_{1} + q_{2}$
$\frac{q}{q_{2}} = \frac{q_{1}}{q_{2}} + 1\ $
$\Rightarrow q_{2} = \frac{q}{\left( 1 + \frac{q_{1}}{q_{2}} \right)}\ $
$\therefore q_{2} = \frac{q}{\left( 1 + \frac{z_{2}}{z_{1}} \right)}\ $
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.