4 cr cm While a moving picture is being screened a boy

Last updated: 6/24/2023

4 cr cm While a moving picture is being screened a boy introduced a glass slab of thickness 3 cm and refractive index 5 between the projector and the screen In order to have a clear picture on the screen the screen should e moved through a distance of 1 cm away 2 cm away 2 1 cm nearer 4 3 cm away D d the focal length is