A single prism can produce a minimum deviation in a light beam. If three such identical prisms are combined, what is the minimum deviation that can be produced in the beam?

Step-by-step solution

To obtain the minimum possible deviation from a combination of three identical prisms, two of the prisms can be placed in opposite orientations (one inverted with respect to the other). The angular deviation produced by the first prism is exactly canceled by the second inverted prism. These two prisms together effectively act as a transparent glass slab, which produces zero net angular deviation (only a slight lateral displacement). The light beam then passes through the third prism, which will produce its own mini