NEET-XII-Physics
33: Thermal and Chemical Effects of Electric Current
- #18An electroplating unit plates 3.0 g of silver on a brass plate in 3.0 minutes. Find the current used by the unit. The electrochemical equivalent of silver is 1.12 × 10-6 kg C-1.Ans : Given:
Mass of silver deposited, m = 3 g
Time taken, t = 3 min. = 180 s
E.C.E. of silver, Z = 1.12 × 10-6 kg C-1
Using the formula, m = Zit, we get:
`` 3\times {10}^{-3}=1.12\times {10}^{-6}\times i\times 180``
`` ``
`` \Rightarrow i=\frac{3\times {10}^{-3}}{1.12\times {10}^{-6}\times 180}``
`` \Rightarrow i=\frac{1}{6.72}\times {10}^{2}``
`` \Rightarrow i=14.89\approx 15\,\mathrm{\,A\,}``
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