Question

A brass plate of surface area 200 cm2 on one side is electroplated with 0.10 mm thick silver layers on both sides using a 15 A 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−1.

Answer 1

The time taken to do the job is 42 seconds

Explanation:

Given:

Current, i = 15 A

Surface area of the plate = 200 $cm^2$,

Thickness of silver deposited= 0.1 mm = 0.01 cm

Volume of Ag deposited on one side = 200 × 0.01 $cm^3$ = 2 $cm^3$

∴ Volume of Ag deposited on both side = 4 $cm^3$

Mass of silver deposited,

m = Volume × Specific gravity × 1000

   = 4 ×  $10^{-3}$× 10.5 ×1000

   = 42 kg

Using the formula, m = Zit, we get:

42 = $Z_Ag$ × 15 × t

  t = 42 ×96500107.9 ×15 s  

  t = 2504.17 s

    = 42 minutes