State the merits and demerits of a parallel combination of resistors.

Explanation

Merits:
( 1 ) If three bulbs are connected in parallel, and one of the bulbs gets fused, then the current continues to flow through the other bulbs and they continue to emit light.
That is why, in house, the electrical appliances are connected in parallel with the main line.
( 2 ) The eqUivalent resistance in the parallel combination of resistors is less than any of the individual resistances. Hence, more current can be obtained by connecting resistors in parallel.
Demerits:
( 1 )In a parallel combination, eqUivalent resistance is smaller than the smallest resistance connected, so total current increases. As a result, current cannot be controlled in the circuit.
( 2 ) If the bulbs working on different voltages (having different voltage rating) are connected in parallel with a given voltage source then each bulb cannot light up with its complete efficiency.
e.g., When three bulbs working on 220V, 230V and 240V respectively are connected in parallel and the same voltage 220V is applied to all the three bulbs then only the bulb working on 220V will light up with complete efficiency.