Question

if two faces of rectangular glass slab are not parallel, what will happen?

Answer 1

If a light ray needs to go in reverse, it needs to rehash a similar way.

This will be conceivable if, if there should arise an occurrence of a section of refractive material, the angle of rate is equivalent to the angle of emergence.

Or on the other hand episode and emanant rays are parallel to one another.

Hope this helps you.