Question

I am asking that one lamp is rated 40 watt at220 volt and the other 60watt at 220 volt supply these are connected in series to a 220 volt supply calculate the current

Answer 1

R'=V^2/P'
R'=220*220/40
R'=1210

R=V^2/P
R=220*220/60
R=2420/3
I=V/R
I=220/(1210+2420/3)
I=660/6050
I=6/55
I=0.1A (approx.)