Q.No.13.6: - Is the filament resistance lower or higher in a 500W, 220V light bulb than in a 100W, 220V bulb?

Q.No.13.6: - Is the filament resistance lower or higher in a 500W, 220V light bulb than in a 100W, 220V bulb?

Ans: -

Power of light bulb                    =        P₁       =        500W

Potential difference        =        V₁       =        220V

Now apply,

                                        P₁       =        V₁²/R₁

                                        R₁       =        V₁²/P₁

                                        R₁       =        (220)²/500

                                        R₁       =        48400/500

                                        R₁       =        96.8 Ω

For second Bulb

Power           P₂       =        100W

Voltage        V₂       =        220V

Now, 

                    R₂       =        V₁²/P₂

                    R₂       =        (220)₂/100

                    R₂       =        48400/100

                    R₂       =        484 Ω

It means that the filament resistance of 100W, 220V light bulb is higher than that of other.