Dual Nature of Light
Light is the electromagnetic radiation that can be detected by a human eye.
And it is within the certain portion of the electromagnetic spectrum called as visible spectrum.
Now, the electromagnetic spectrum has mainly seven types of waves as,
Many of scientists have said that the light is of particle nature.
But many of scientists have said that light is of wave nature.
Finally, it has been decided that the light has dual nature, particle as well as wave.
Let’s discuss the dual nature of light.
In classical mechanics, light is considered as a wave. Because, it undergoes interference, diffraction, and polarisation.
And interference, diffraction, and polarisation are the properties of waves.
In classical physics, light is an electromagnetic wave.
Let the electric field oscillations along the y-axis and perpendicular to it magnetic field oscillation along the z-axis then the light will propogate along x-axis.
That means perpendicular to these two quantities (magnetic field and electric field). So, all three are mutually perpendicular.
Light is a transverse wave, because it shows the polarisation which is the property of transverse wave.
First of all, Newton thought that light is a particle and gave corpuscular theory.
At the same time Huygen thought that the light is a wave and gave Huygen wave theory.
But later, very famous experiment was done by the Thomas Young called Young’s double slit experiment.
In which the Thomas Young showed that the light undergoes the interference and interference is the property of a wave.
Hence, the light has wave nature.
Later, one famous phenomenon that is photoelectric effect was discovered by the Hertz.
But their observation could not be explained by the light as a wave.
After that, Einstein in 1905, took light is a particle to explain the photoelectric effect.
And for that he got the Nobel prize in physics in 1921.
Another phenomenon is the compton effect that also establishes that the light behaves as a particle.
Finally, de Broglie said that the light has wave nature as well as particle nature.
When light propagates, it propagates as a wave and when the light gives some energy to material particle then it behaves like a particle.
Now, the particle-like electrons also have the particle as well as wave nature.
In classical physics, electrons treated as the particle because it has mass, charge, etc.
But, in another equipment like the electron microscope, the electron behaves like a wave nature.
Hence, the particle, like electrons also have the dual nature and light has the dual nature.
This wave-particle duality is the general property.
Hence, everything has got a dual nature (wave and particle nature).
First of all, Newton was said that the light has particle nature.
But at the same time, Huygen said that the particle has wave nature.
Later, Einstein used light as a particle to explain the phenomenon of photoelectric effect.
But, finally De Broglie said that the light has both nature particle as well as wave.