Object magnification after Convex surface

[dimensionless]

I have an object that is surrounded by air and sits a distance U=30 from a convex surface. The convex surface has a radius of R=5. The index of refraction of the refracting media is n=1.33. How do I determine the magnification of the object?

[siddharth]

I think, if you find out where the object falls after refraction using the lens maker forumla(R_2 = \infty ), you can calculate the magnification using some simple geometry
http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/lenmak.html

[dimensionless]

It is not a thin lense. It is a convex interface between two materials.

[siddharth]

It is not a thin lense. It is a convex interface between two materials.
My mistake then.
The general equation of refraction at a spherical surface will be

[tex] \frac{\mu_2}{v} - \frac{\mu_1}{u}=\frac{\mu_2 - \mu_1}{R} [/itex]