The exact solution of the scattering of a point source by a shpere and an infinite cylinder is derived and computed.
The type of the point source is an impulse point source. The exact solution in the case of teh sphere is derived and enlarged to the case of the infinite cylinder. There is a resonable analogy between two cases, and a remarkable difference between the result in the illuminated region and that in the shadow region of two cases.
This result is to be checked by experiments.