Question

An electric bulb is rated 220 V 100 W . what is the resistance of the bulb..??

Answer 1

Given Power = 100W, Voltage or potential = 220

We know that, 
Power law equation P = i × V.
                                100 = 220 × i
                                 i = 5/11 Amperes

From ohms law, V = iR
                         220 = 5/11 × R
                         R = 220 × 11/5
                         R = 440Ω


                                    

Answer 2

I = 5/11 A

R = V/I

= 220×11/5 = 440Ω