Question

what is Einstein ring?

Answer 1

http://en.wikipedia.org/wiki/Einstein_ring

Answer 2

it is given there i saw that.. but not clearly explained theoretically...

Answer 3

It's an example of gravitational lensing:
http://en.wikipedia.org/wiki/Gravitational_lens

...which is an effect predicted by General Relativity, G.R., and as you can see, very well observed.

If you want to understand the theory of it, you need to understand G.R. I wrote a sub-thesis on this topic a few years ago. It's good stuff.

Answer 4

will you give that to me...??

Answer 5

I actually don't have it electronically any more, so I can't.

Answer 6

ok no problem...