Question

two electric bulbs rated 100W :220V and 60W:220V are connected in parallel to an electric mains of 220 V .Find the current drawn from the mains.

Answer 1

As the bulbs  are connected in parallel then resistance of each lamp can be calculated as ,

We know that power is given by P= V^2/ R.

So rearranging R= V^2/P.

For 100W Lamp , R=220^2/100=484 ohm.

For 60 W lamp , R=220^2/60=806.67 ohm.