1. The figure illustrates a number of optical lenses made of glass with index of refraction n.

If used in eyeglasses, that type of lens would help for: (choose far sighted or near sighted) a. W, for a .... person. b. Y, for a .... person. c. X, for a .... person.

r1 r2 r2 X Y r1 r2 r2 r1 Z r1r2 r1 r1 Y W r2 r1 r1 r2 2 X