Two identical heaters rated 220 V, 1000 W are placed in series with each other across 220 V line; then the combined power is

Let the resistance of the two heaters be denoted by R1 and R2, respectively. ThenR1V2P1and  R2=V2P2If the resistance of the series combination is denoted by Rs and the corresponding power by Rs is Ps, then Rs=R1+R2. So V2PS=V2P1+V2P2.Ps=P1P2P1+P2=1000×10002000=500W