Two lamps, one rates 100W; 220V, and the other 60W; 220V are connected in parallel to electric mains supply. Find the current drawn by two bulbs from the line, if the supply voltage is 220V.

Rating of first lamp is given as : P1=100 W and V1=220 V
Thus resistance of first lamp R1=V1²/P1=220²/100=484 Ω
Supply voltage Vs=220 V
Current drawn by first lamp I1=Vs/R1=220/484=0.45 A
Rating of second lamp is given as : P2=60 W and V2=220 V
Thus resistance of second lamp R2=V2²/P2=220²/60=806.67 Ω
Current drawn by second lamp I2=Vs/R2=220/806.67=0.27 A
Total current drawn by both lamps = I1 + I2 = 0.45 A + 0.27 A = 0.72 A