At what thickness will a thick convex-concave glass lens in air
(a) serve as a telescope provided the curvature radius of its convex surface is ΔR = 1.5 cm greater than that of its concave surface?
(b) have the optical power equal to —1.0 D if the curvature radii of its convex and concave surfaces are equal to 10.0 and 7.5 cm respectively?