Question

the resistance of the filament of an electric bulb changes with temperature if an electric bulb is rated 220 volt and 100 watt is connected( 220*0.8) volt sources than the actual power would be​

Answer 1

Hey Dear,

◆ Answer -

less than 64 W

◆ Explaination -

Initial resistance of bulb filament is calculated by -

R = V^2 / P

R = 220^2 / 100

R = 484 ohm

Estimated power of bulb when connected with 220×0.8 V battery is -

P = V^2 / R

P = (220×0.8)^2 / 484

P = 64 W

We know that resistance of bulb decreases with increase in temperature. Thus actual power will be somewhat lesser than 64 W.

Thanks dear...