Definition of Ray(2/2) In free space,rays are rectilinear In presence of concentrated obstacles rays are piecewise-rectilinear and wavefronts can be of various kinds(see further on) In non-homogeneous media rays can be curved(not treated here) Ex.I Sperical wave and Ex.2 reflected spherical wave and rectilinear rays piece-wise rectilinear rays Rays are normal to wavefronts Point source Wavefronts expanding from point sourceDefinition of Ray (2/2) • In free space, rays are rectilinear • In presence of concentrated obstacles rays are piecewise-rectilinear and wavefronts can be of various kinds (see further on) • In non-homogeneous media rays can be curved (not treated here) Ex.1 Sperical wave and rectilinear rays Ex.2 reflected spherical wave and piece-wise rectilinear rays Point 1 source s0 s1