What is the shape of the wavefront in each of the following cases ?
(a) light diverging from point source.
(b) light emerging out of a convex lens when a point source is placed at its focus.
( c) the portion of the wavefront of light from a distant star intercepted by earth.
A. Cylindrical wavefront
B. Plane wavefront
C. Converging wavefront
D. Diverging wavefront
