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?

As the two lamps are connected in parallel, the voltage across each of them will be the same.

Let I₁ be the current drawn by 100 W bulb:

I₁ = $\dfrac{\text{P}}{\text{V}} = \dfrac{100}{220} = \dfrac{5}{11} \text{ A}$

Let I₂ be the current drawn by 60 W bulb:

I₂ = $\dfrac{\text{P}}{\text{V}} = \dfrac{60}{220} = \dfrac{3}{11} \text{ A}$

∴ Current drawn from line = I₁ + I₂

$= \dfrac{5}{11} + \dfrac{3}{11} \\[1em] = \dfrac{5 + 3}{11} \\[1em] = \dfrac{8}{11} \text{ A} \\[1em] = 0.727272 \text{ A} \approx 0.73 \text{ A}$

Hence, 0.73 A current flows through the line.