Question

angle of incident increases, angle of deviation decreases, but after a certain value of angle of incident, the angle of deviation increases. What is the value of the angle of incident called? Does these angles light all colors for same?

Answer 1

Screen is just an device or an instrument where the image formed is to be observed. If the screen is removed, the lens will continue to form the image on its focus. Thus, on removing the screen and on looking through the lens in the direction of the object the image of the distant tree is inverted and formed at the focus .Critical angle.its same for all colours