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