Two lamps, one rated 100 W at 220 V and the other 60 W at 220 V

Question 15:

Two lamps, one rated 100 W at 220 V, and the other 60 W at 220 V, are connected in parallel to electric mains supply. What current is drawn from the line if the supply voltage is 220 V?

Solution:

Both the bulbs are connected in parallel. Therefore, potential difference across each of them will be same that is 220 V, Current drawn by the bulb of rating 100 W is given by

I=P/V

 =100/220=0.4545...A

Similarly, current drawn by the bulb of rating 60 W is given by

I=P/V

 =60/220=0.2727...A

∴ the total current drawn from the line =0.4545+0.2727=0.727A