Question

Two voltameters, one of copper and another of silver, are joined in parallel. 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. $q\frac{z_{2}}{z_{1}}$

Answer 1

Answer: (B)

We know $m=zq$
$\Rightarrow z\,\propto\, \frac{1}{q}$
$\therefore \frac{z_{2}}{z_{1}}=\frac{q_{1}}{q_{2}}$
Total charge $q= q_{1} + q_{2}$
$\therefore \frac{q}{q_{2}}=\frac{q_{1}}{q_{2}}+1$
$\Rightarrow q_{2}=\frac{q}{\left(1+\frac{q_{1}}{q_{2}}\right)}$
$\therefore q_{2}=\frac{q}{\left(1+\frac{z_{2}}{z_{1}}\right)}$