Page 111 - Physics - XII
P. 111

6.  Remove the glass slab and draw a straight line through R, S which represent emergent ray and meets
              face DC at Y. Draw a normal N N  at Y and join XY. Measure the angle N YR, i.e., angle e which comes
                                                4
                                             3
                                                                                      4
              to be equal to angle i.
          7.  Produce  PQX  forward  to  cut  DC at  Z.  Draw  TZ  perpendicular  to  RSY.  TZ  measures  the  lateral
              displacement ‘d ’.
          8.  Repeat the experiment by taking the glass slabs of diff erent thickness.

                                           N 1

                               P
                                    Q
                                            Angle of incidence
                                          i
                               A            X                     Air    B
                                                         N
                                                          3    Glass
                                             r                               Glass slab
                                  Refracted
                                     ray
                                                               Angle of
                                                               refraction
                                                       r
                                           N
                                            2
                                                                    Z
                               D                       Y       d         C
                                                           e
                                           Angle of          T   R
                                           emergence
                                                                                      Lateral
                                                                           S          displacement
                                                                                d
                                                        N
                                                          4
                                                            Emergent ray

                                      Fig. 4.1:  Refraction of ray of light through a glass slab

          Observations

          Least count of protractor = _____ degree
          Least count of metre scale = _____ mm = _____ cm

             S.    Thickness of glass slab,    Angle of incidence,    Angle of emergence,      Lateral deviation,
            No.             t (cm)                 ∠i (degree)             ∠e (degree)               d (cm)

             1.                t 1
             2.                t 2

             3.                t 3

             4.                t 4

             5.                t 5
             6.                t 6


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