Glass Marbles

A plane mirror  is a mirror with a planar reflective surface. For light rays striking a plane mirror, the angle of reflection equals the angle of incidence. The angle of incidence is the angle between the incident ray and the surface normal.

Combustion Boats are used in laboratories for chemical analysis. … The surface of porcelain combustion boats are glazed all over with the exception of outside bottom. The bottom of a combustion boat is generally flat that allows it to firmly placed on a planar surface.