The stamp on an electic bulb reads 220V-60 W. if the supply voltage available is 100 V then what current will be drawn by the bulb ?

Explanation

Voltage rating, V=220V
Power rating, P=60W
As `P= (V^(2))/(R )` (R is the resistance of heating element)
`:. R= (V^(2))/(P) =(220 xx 220)/(60) = 806.6 Omega`
Applied voltage, V.=100V
Then current, `I = (V.)/(R ) = (100)/(806.6) = 0.12A`