53. From Eq. 35-10, if -1 1 1 r1r2 f " - = r1 r2 r2 - r1 is positive (that is, if r2 >r1), then the lens is converging. Otherwise it is diverging. (a) Converging, since r2 "and r1 is finite (so r2 >r1). (b) Diverging, since r1 "and r2 is finite (so r2 (c) Converging, since r2 >r1. (d) Diverging, since r2 Wyszukiwarka