Expt. : 11                                     Refractive index  of prism

Aim :

          To determine refractive index of material of prism by plotting i - D graph using pin method

Apparatus :

           Drawing board, drawing pins, white sheet, prism and protractor

Formula:

                m  =  sin [ (A + D_m ) / 2 ] / sin ( A/2 )

                where m is refractive index of material of prism

                          A is angle of prism

                          D_m is angle of minimum deviation                       

Calculations :

                       [Click here for the sample trace for prism]

                        [Click here for the sample i - D graph for prism]

            Angle of prism is 60^o

            Angle of minimum deviation is 38^o

                    m  =  sin [ ( A + D_m ) / 2]  / sin ( A/2 )

                        =  sin [ ( 60 + 38 ) / 2 ] / sin ( 60/2 )

                        =  1.5

Result :

        Refractive index of material of prism is 1.5