Question

explain Huygens principle of secondary wavelets and on the basis of this principle established the laws of reflection

Answer 1

Huygens' principle. The first person to explain how wave theory can also account for the laws of geometric optics was Christiaan Huygens in 1670. ... Every point on a wave-front may be considered a source of secondary spherical wavelets which spread out in the forward direction at the speed of light.