power 4dTwo lenses have power of (i) + 2 d (ii) -4D. What is the nature and focal length of each lens? b. An object is kept at a distance of 100 cm from lens of power -4D. Calculate the image distance.To find the effective power of a combination of a convex lens and a concave lens, we can follow these steps: 1. Identify the Powers of the Lenses : - The power of the convex lens (P1) is given