Question

What are the conditions for the light to act as a ray, wave and particle?

Answer 1

Light energy can be described as a wave, a particle (or photon), or a combination of both (called the wave-particle duality). Another approach is to consider light energy as a ray. Huygens' theory of light refraction, based on the concept of the wave-like nature of light, held that the velocity of light in any substance was inversely proportional to its refractive index. Einstein believed light is a particle (photon) and the flow of photons is a wave. The main point of Einstein's light quantum theory is that light's energy is related to its oscillation frequency.