Page 61 - Electrician - TT (Volume 1)

ELECTRICIAN - CITS

Electrodes
The conductor or terminal, usually metallic through which an electric current enters or leaves is called an electrode.
Anode

One terminal of a device that loses electrons in the external circuit during normal operation is called anode. In a
battery negative electrode is the anode and positive electrode is the cathode.
Electrolysis of copper sulphate solution

Consider solution of copper sulphate (CuSO ). Two copper electrodes are placed in the solution. When CuSO
4
4
is dissolved in water, its molecules split up into Cu++ and SO - ions. When these electrodes are connected to a
4
battery the Cu++ ions go to the negative electrode and SO - ions go towards the positive electrodes.
4
The movement of the ions constitutes a flow of electric current through the electrolyte. In external circuit the
current is due to the motion of electrons.

Faraday’s laws of electrolysis

Faraday determined two laws which govern the phenomenon of electrolysis.
First law: The mass of the substance liberated or deposited at an electrode during electrolysis is directly
proportional to the quantity of electric charge passed through the electrolyte.

Mαq
M = zq
M = zIt (q=It)

48

CITS : Power - Electrician & Wireman - Lesson 13-19