Question

light passes through a rectangular glass slab and through a triangular glass prism using proper ray diagram explain in what way does the direction of the two emergent beams differs with respect to the incident beam of light

Answer 1

In case of a prism the deviation D of the emergent ray from incident ray AB is given by :
                        Mu = sin ((A+D)/2 )  /  sin (A/2)

In case of a glass slab there is no angular deviation. There is a lateral displacement L  of the incident ray thru a slab of thickness t :
                  L = t sin (i - r) / cos r