Answer to Question #38973 in Optics for Nick

Question

While a moving picture is being screened, a boy introduced a glass slab of thickness 3 cm and refractive index 1.5 between the projector and the screen. In order to have a clear picture on the screen, the screen should be moved through a distance of
(1) 1 cm away
(2) 1 cm nearer
(3) 2 cm away
(4) 3 cm away