An object is kept at a distance of 100 cm from lens of power - 4 D

power 4dTo find the focal length of the combination of two thin lenses in contact, we can follow these steps: Step 1: Identify the Powers of the Lenses We have two lenses: - Lens 1 has a power ( P1 = +4Given, Power of convex lens=4D. Placed at 40 cm from a wall. To Find, Distance of a candle. Solution, It is given that ,Power = 4D. Then, P = 1f. So, 4 D = 1f