State the significance of the following devices in domestic circuits: (i) Main switch (ii) Mains fuse (iii) Electricity meter.

(i) Main switch in domestic circuits is used to switch on or switch off the power supply.
(ii) Mains fuse acts as a safety device in domestic circuit and prevents damage to the appliances and the electric circuit due to overloading and short circuiting.
(iii) The electricity meter installed in the domestic circuit is used to measure the quantity of electrical energy being used in the circuit during a given time.