A metal "hump" is placed on the surface of the infinitely large conducting plate as shown on the picture. The hump has a form of a hemisphere, radius R, with the center O lying in the plate's plane. A point charge q is placed outside the hump, on the line that is going through O and is perpendicular to the surface of the plane. Distance between charge and point O is a. Find the electric field distribution in the region above the plane.