This ray is not bent. It should pass through the intersection of the other rays that you have drawn. Diverging lenses only form virtual images. R is negative, if x o and the center curvature are on the same side of the lens. R 1 is the radius of the surface closest to x o .
Many optical instruments have more than one optical element.
A combination of mirrors and lenses can be analyzed by treating the image of the first element as the object of the second element, and so on. If the image of the first element falls behind the second element we can still use the lens or mirror equation, but we then must use a negative object distance x o . A contact lens is made of plastic with an index of refraction of 1.5. The lens has an outer radius of curvature of 2cm and an inner radius of curvature of 2.5cm. Both R 1 and R 2 are positive.