An initially parallel cylindrical beam travels in a medium of refractive index `mu(I)=mu_0+mu_2I`, 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.
30 . At the beam enters the medium, it will

Options

A. travel as a cylindrical beam
B. diverge
C. converge
D. diverge near the axis and converge near the periphery

Answer

B