A bulb is rated as 250 V; 0.4 A Find its:

(i) power, and (ii) resistance.

(i) We know that

V = 250V, I = 0.4amp

Power = VI = 250X0.4 = 100watt

(ii) We have,

V = 250V, I = 0.4amp

We know that

P = I²R

100 = 0.4²XR

R = 625ohm