Question

What is the definition of light .

Is light a ray or wave or particles(photons).

Answer 1

Light is a form of energy which gives sensation of vision. It travels in the form of electromagnetic wave.
Light exhibit dual characteristics that is, in certain experiments light show wave-like behavior and in certain other experiments light exhibit particle behavior. This makes light have a complimentary structure of wave and particle; a fact that is hard to visualize. Nevertheless, we can safely assume that light travels in the form of wave packets that carries energy, just visualize a packet made of waves. This packet behaves like particle at times and wave in the other time.

Phenomena like interference, diffraction, polarization of light show the wave behavior of light while other phenomena like photoelectric effect, blackbody radiation, Raman effect etc, show particulate behavior of light.