Question

Using Huygens’ geometrical construction of wavefronts, show how a plane wave gets reflected from a surface. Hence, verify laws of reflection.

Answer 1

➡The Dutch physicist Christian Huygens imagined each point of a propagating disturbance as capable of originating new pulses that contributed to the disturbance an instant later. To show how his model of light propagation implied the laws of geometrical optics, he formulated a principle which says that each point on the leading surface of a wave disturbance may be regarded as a secondary source of spherical waves, which themselves progress with the speed of light in the medium and whose envelope at later times constitutes the new wavefront. Notice that the new wavefront is tangent to each wavelet at a single point.