question_answer

Directions Q. No. 1 are based on the following paragraph. An initially parallel cylindrical beam travels in a medium of refractive index \[\mu (I)={{\mu }_{0}}+{{\mu }_{2}}I,\] where \[{{\mu }_{0}}\] and \[{{\mu }_{2}}\] are positive constants and \[I\] is the intensity of the light beam. The intensity of the beam is decreasing with increasing radius. The initial shape of the wavefront of the beam is -     AIEEE  Solved  Paper-2010

A) planar

B) convex

C) concave

D) convex near the axis and concave near the periphery