a) Two lenses A and B have power of i) `+2D` and ii) `-4 D` respectively. What is the nature and focal length of each lens?
b) An object is placed at a distance of 100 cm from each of the above lenses A and B. Calculate i) image distance, and ii) magnification, in each of the two cases.

Explanation

a) Lens A is convex, `f=+50 cm`, Lens B is concave, `f=-25 cm` b) Lens A: v`=+100 cm`, `m=-1,` Lens B: `v=-20 cm`, `m=0.2`