Solution:
Here R2 < R1
(because voltage decreases from 220 V 220 x 0.8 V. It means heat produced decreases)
Hence, the actual power would be between 100 x (0.8)2 W and (100 x 0.8) W
The resistance of the filament of an electric bulb changes with temperature. If an electric bulb rated 220 volt and 100 watt is connected to a (220 x .8) volt source, then the actual power would be
Here R2 < R1
(because voltage decreases from 220 V 220 x 0.8 V. It means heat produced decreases)
Hence, the actual power would be between 100 x (0.8)2 W and (100 x 0.8) W