Albert Einstein in 1905 developed a theory which stated that the light has dual nature. Light acts as a particle and a wave. Quantum of the energy is associated with each particle and it is called a photon. This energy of the photon can be expressed by using Planck’s equation. The hypothesis presented by Einstein helped to explain that the light is emitted when the current is passing through the gas in the cathode ray tube. The atom is said to be in the ground state when it has the lowest potential energy. When the current is passing at the low pressure the potential energy of the atom is increased. At the state when an atom has high potential energy than the ground state then it is said to be excited. At this state, the atom is not stable and eventually, it will return to the ground state and in this process, energy is lost in the form of electromagnetic radiation. The passing of an electric current through the elemental gas causes the emitting of characteristic color. If the light is passed through the prism then it splits into various bands of the light at the specific wavelengths and these bands are called as line-emission spectrum for that specific element. Mathematically first line emission spectrum was described for Hydrogen.
In a classical view, the particle is a concentration of energy and of the other properties of time and space while wave spread out over the large region of time and space. Mainly this is the concept of quantum physics that every quantum or particle can be described partly not only in the terms of particles but in the terms of waves also.
Dual Nature of Matter
Lewis de-Broglie proposed the dual nature of the matter in 1924 and stated that just like radiation, matter also has dual characteristics. He presented the concept of dual nature of matter which was based on the following observations.
- The universe is composed of electromagnetic radiation and matter. Both of them are forms of energy and they can be transformed into each other.
- The matter has symmetry. Just like the dual nature of radiation, the matter should also have dual nature.
According to Broglie’s concept about matter waves matter also has dual nature. In other words, moving matter shows the wave-like properties such as diffraction and interference and when it is resting it shows the properties of the particle. So, the matter has a dual nature. The waves which are associated with the moving particles are called de-Broglie waves or matter waves.
Through the work of Niels Bohr, Albert Einstein, Arthur Compton, Max Planck, and Louis de Broglie and many other scientists, the current scientific theory is holding the fact that all of the particles exhibit the wave nature and the vice versa. The properties of light and matter show that both the light and matter have a dual nature of wave-particle. While one thing should be kept in mind that the properties of wave and particle are elementary