Question

What is meant by power of a lens?
Two lamps rated 100 w and 220 v and other 60 w and 220 v find current on each

Answer 1

Power of a lens is defined as the reciprocal of its focal length

We know that
P=VI
100=220*I
or, 100/220=I
so, I=0.45A

again, P=VI
60=220*I
60/220=I
so, I= 0.27 A

hope it helps....

Answer 2

Power of a lens is defined as its converging or diverging ability.
We know....Power= p.d.×current...
in the 1st lamp power=100W and p.d.=220V,so current=100/220 A= 5/11 A=0.454 A(approx)
the second lamp has power=60 W and p.d.=220V,so current=60/220A=3/11A=0.272 A ( approx).....Hope it HELPS......