3 180 2A 4 180 3A Two identical thin plano convex glass

Last updated: 6/13/2023

3 180 2A 4 180 3A Two identical thin plano convex glass lenses refractive index 1 5 each having radius of curvature of 20 cm are placed with their convex surfaces in contact at the centre The intervening space is filled with oil of refractive index 1 7 The focal length of the combination is 1 25 cm 2 50 cm 3 50 cm 4 20 cm