Question

An ammeter and a copper voltmeter are connected in series in an electric circuit through which a constant direct current flows. The ammeter shows $0.525A$ if $0.6354g$ of copper is deposited in one hour. The percentage error in the ammeter reading is:(nearest integer value)

Answer 1

Current shown by ammeter $=0.525A$
Actual current flow, $i=\frac{w}{E\times t}\times 96500$ (where E = Molar mass/ valency factor)
$i=\frac{0.6354\times 96500}{\frac{63.54}{2}\times 60\times 60}$ = 0.536 A
% error = $\frac{0.536-0.525}{0.536}\times 100$ $=2.05\equiv 2.0$