the focal length of the silvered part=-.2m
for non silvered part apply lens maker's formula
then apply
P eq=2P l+p m
A thin hollow equiconvex lens silvered at the back converges a parallel beam of light, at a distance of 0.2m in front of it. Where will it converge the same light, if filled with water (µ = 4/3).
Yesh:
I think the first case it will act as a concave mirror....
With some radius of curvature... which u will be able to find easily...
Then you will have to use a combination of one curved refracting surface with a mirror!
the focal length of the silvered part=-.2m
for non silvered part apply lens maker's formula
then apply
P eq=2P l+p m