Question

A plate of area `10 cm^2` is to be electroplated with copper `(density 9000 kg m^(-3))` to a thickness of 10 micrometres on both sides, using a cell of `12 V`. Calculate the energy spend by the cell in the process of deposition. If this energy is used to heat `100 g` of water, calculate the rise in the temperature of the water. ECE of copper `= 3 xx 10^(-7) kg C^(-1)` and specific heat capacity of water `= 4200 J kg^(-1) K^(-1)`.

Answer 1

`m=9000xx10xx10^4xx10xx10^(-6)xx2`
`=18xx10^(-5)kg` ltbr. `m=ZQ`
`Q = m/Z = (18xx10^(-5))/(3xx10^(-7)) = 600C`
Energy spent `= EQ = 12xx600 = 7200J`
`Delta Q = msDelta theta`
`7200=0.1xx4200 Delta theta`
`Delta theta = 72/4.2 = 17^@C`