If bulb rating is 100 walt and 220 V then determine
(a) Resistance of filament
(b) Current through filament
(c ) If bulb operate at 110 volt power supply then find consumed by bulb.

Explanation

Bulb ratting is 100 W and 220 V bulb means when 220 V potential difference is applied between the two ends then power consumed is 100 W
Here V=220 Volt
p=100 W
`V^(2)/R=100" So "R=484 Omega`
Since Resistance depends only on material hence it is constant for bulb ltbtgt `I=V/R=220/(22xx22)=1/11Amp.`
Power consumed at 110 V
`therefore" Power consumed"=(110xx110)/484=25W`