As you rotate the glass block clockwise, the light will undergo refraction and emerge and cuts the like XY to the left of W. As the angle increases, the displacement of the light ray cutting on XY increases. When the angle of rotation increases, you can see that the light ray enters from the shorter edge of the glass block, and the light ray emerge out and cuts XY to the right of W. When the angle approaches 90o, the displacement from W decreases When the block is 90o, the li

To get a sharp image on the screen, there are various methods and concepts that you have learned and can be applied here. View the video for the explanation: