Question

In our homes, we receive the supply of electric power through a main supply also called mains, either supported through overhead electric poles or by underground cables. In our country the potential difference between the two wires (live wire and neutral wire) of this supply is 220 V.

Consider the following circuits : In which circuit will the power dissipated in the circuit be (I) minimum (II) maximum ? Justify your answer.

Two lamps, rated 100 W; 220 V and 60 W; 220 V are connected in parallel to electric main supply of 220 V. Find the current drawn by the two lamps from the supply.

Find the current flowing through the following electric circuit :

Consider the following combinations of resistors : The combinations having equivalent resistance 1 Ω is/are :