40 Two identical thin plano convex glass lenses refractive

Last updated: 6/11/2023

40 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 2015 a 25 cm b 50 cm c 50 cm d 20 cm 144