A light bulb is rated 100 W for 220 V ac supply of 50 Hz. Calculate
(i) the resistance of the bulb,
(ii) the rms current through the bulb.

Explanation

(i) As p = `(V^(2))/(R)`
`thereofore " " R = (V^(2))/(P) = (220 xx 220)/(100) = 484 Omega`
(ii) ` V_(rms) = 220 ` V
` I_(rms) = (V_(rms))/(R) = (220)/(484) = 0.45 A `