An arc lamp requires a direct current of 10 A and 80 V to function. if it is connected to a 220 V(rms), 50 Hz AC supply, the series inductor needed for It to work is close to :
For DC
R=VI=8010=8Ω
For AC
I=10A
I=VR
10=220√R2+ω2L2
R2+ω2L2=484
L2=484−642πν
L2=4202×3.14×50
L=0.065H