Question

7. A convex lens is made of glass (n = 1.5). When an object is placed 15 cm in front of the lens, its image is formed 7.5 cm behind the lens. The lens is then submerged in water and an object is placed 15 cm in front of it. 1. Where will the image of the object be formed? 2. What is the magnification of the image?

Answer 1

solution (77 given: refractive index of lems is ng = 1.5 object distance do = -15cm image distance d; = 47.5cm from rem formula do do di 1-15)×(7.5) - 15-7.5 f d; fe dood; do -d; (f = 5cm focal length of lem in water in here n = 1.33 ( for wat en t=115-11x5 = 19.56cm i object distance in water is do= -15cm so from em formula di = f do

here f= f = 19.56cm .: d; = (-15)*(19.56) -15 +19.56 (d; : -54.34 cm] so image formed in front of the lens at a distance of 64.34cm. (21 magnification of the image is -13 m = 4.29 /