If a bulb rated as (25W-220V) is connected in series to another bulb rated as (100W-220v) to 220 volt, then which bulb will give more illumination.

Explanation

For first bulb `R_(1)=(V^(2))/(P)=((220)^(2))/(25)=193 6Omega`. For second bulb `R_(2)=(V^(2))/(P)=((220)^(2))/(100)=484Omega`
Power P=`I^(2)R` and in series combination 1 is constant so `P prop R`
Since R is greater for first bulb therefore first bulb will more glow.