Refraction in a Biconvex Spherical Lens
Consider a biconvex spherical lens with left radius and center and right radius with center at . A ray enters the lens at , passes through it and leaves it at . This Demonstration shows the ray and its corresponding angles.
The angles are:
is the angle
 A. Halpern, 3,000 Solved Problems in Physics, New York: McGraw-Hill, 1988.