One surface of a lens is convex and the other is concave, If the radii of curvatures are `r_1` and `r_2` respectively, then the lens will be convex if

Options

A. `r_1 gt r_2`
B. `r_1 =r_2`
C. `r_1 lt r_2`
D. `r_1 = l//r_2`

Answer

C