FACTS & THEORIES ABOUT DUAL NATURE OF LIGHT

Isaac Newton, in 1670, established that the perfectly straight lines of reflection demonstrate the light’s particle nature since only particles can travel in such straight lines. He explained refraction by saying that the particles of light accelerate laterally when they enter a denser medium.

APPLICATIONS AND LIMITATIONS OF HUYGEN’S PRINCIPLE

Huygen’s Principle states that each and every point on a wavefront serves as a source of wavelets which then spread forward at the same speed. The new wavefront is in a line tangent to all of the wavelets.