Question

what is angle of deviation and it is formed between which rays??
what is angle of emergence??
WHY RECTANGULAR SLAB DOES NOT SHOW DISPERSION?​

Answer 1

Answer:

1)Angle Of Deviation- The angle equal to tha difference between the angle of incidence and angle of refraction.

2)Angle Of Emergence- the angle of emergence is the angle of light coming out of a medium.

3)Rectangular Slab does not show dispersion because the opposite sides of the slab are parallel and therefore different colors emerge parallel to each other.

Answer 2

Answer:

• The angle that is formed between the incident ray and the refracted ray when they are produced forwards and backwards respectively is called angle of deviation.

• The angle of emergence is the angle formed between the emergent ray and the normal at the point of emergence.

• You do know that  when the dispersed rays from one prism is passed through another upside down prism, the colors recombine again right?

Well, if you keep these two prisms in contact with each other, what you get is a parallelogram. The sides are parallel to each other.

   Now, if you consider a rectangular glass slab, it is also a parallelogram right? So it acts like the two prisms kept together and so no dispersion occurs.

        Thus, if the surfaces are parallel to each other no dispersion occurs.

Hope this helps you : )