Question

An electric fuse of rating 3A is connected in a circuit in an electric iron of power 1kW which operates at 220V. What would happen?Explain.

Answer 1

Power of the iron = 1 kW = 1000 W 
Current through the circuit = 1000/220 = 4.55 A 
It is given that the rating of the fuse is 3 A. The current drawn by the iron is more than the current rating of the fuse. Hence, each time the iron is switched on, the fuse will get heated, melt and break the circuit.