Physics Optics questions from NEET UG 2002.
For the given incident ray as shown in the figure, the condition of the total internal reflection of this ray and the minimum refractive index of prism will be: 
A bulb is located on a wall. Its image is to be obtained on a parallel with the help of a convex lens. If the distance between parallel walls is ' $d$ ' then the required focal length of the lens placed in between the walls is: