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Thermal and Chemical Effect of Current — Physics STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 SciencePhysicsThermal and Chemical Effect of Current2 Marks
Question
A brass plate having surface area $200cm^2$ on one side is electroplated with $0·10mm$ thick silver layers on both sides using a $15A$ current. Find the time taken to do the job. The specific gravity of silver is $10.5$ and its atomic weight is $107.9 g/mol$.
✓

Answer

$\mathrm{I}=15 \mathrm{~A}$ Surface area $=200 \mathrm{~cm}^2$, Thickness $=0.1 \mathrm{~mm}$ Volume of Ag deposited $=200 \times 0.01=2 \mathrm{~cm}^3$ for one side For both sides, Mass of $\mathrm{Ag}=4 \times 10.5=42 \mathrm{~g}$
$\text{Z}_{\text{Ag}}=\frac{\text{E}}{\text{F}}=\frac{107.9}{96500}$
$\text{m}=\text{ZIT}$
$\Rightarrow42=\frac{107.9}{96500}\times15\times\text{T}$
$\Rightarrow\text{T}=\frac{42\times96500}{107.9\times15}=2504.17\text{sec}=41.73\text{min}\approx42\text{min}$

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