After extensive research, scientists have found that light behaves as a particle some times and as wave in other instances. When light behaves like a particle, scientists term these particles as quantum or photon. Max Plank in 1900, proposed the light quantum existence by describing light as a packet of photons.

Photons are nothing but small packages of light-energy. Precisely, photons don't have specific volume as they are dust like specks. As photons are arranged always in electromagnetic wave form, it indicates that these photons are just a portion of wave.

Frequency of photon forms a single spectrum-line which represents an exact color or wavelength. In 1900, Max Planck came up with a theory that, light contains packages of photons. As per his theory, the photon energy is equivalent to the frequency of electromagnetic wave ('multiplied') by "h" constant, called the Planck's constant.

Nevertheless, this constant is small, since every photon carries a small amount of energy. Even Isaac Newton also came up with the idea that 'light is a particle'. Scientists discovered that light also travels in wave form. This is because light also exhibits wave-like characteristics. Diffraction of light as it passes through a corner, exhibits wave-like behaviour.

If light was a particle, then these particles should not have bent while passing through a corner. These waves were termed as matter waves. Wave is nothing but a constant phenomenon, because when wave travels, their electromagnetic field moves at definite infinite points in small portion of space.

Again, the age old debate crops up: "Is light a particle or a wave?" light cannot be both, since models of particles and waves are different. Light behaves differently while traveling and passing through different mediums. Thereby, the conclusion depends entirely on what you are actually experimenting on? Einstein's theories about light energy describe light as a particle. Whereas, Huygens principle describes accurately that light exhibits all wave motion forms.

Even several theories have come up stating light is a combination of both particle and wave. But none of the theories prove that light is either.