Question

Calculate the current through a 60W lamp rated for 250V. If the line voltage falls to 200V, how is the power consumed by the lamp affected.

Answer 1

We know,

P = V² / R

=> R = V² /P = (250*250)/60 = 1041.67 Ω

Power consumed by bulb = (200)²/1041.67 = 38.40 W

So, 60W bulb act as 38.40W bulb.