Question

Two thun convex lens of power 4D and 6D are placed co axiaaly at a distance of 20 cm pArt find the focal length and power of the com bination of lenses

Answer 1

(a)40 cm to left of 1st lens

(b)40 cm to right of 1st lens

(c)40 cm to left of second lens

(d)40 cm to right of second len