Dual nature of Light;

Add caption

What are the two nature of light ?  What is meant by dual nature of light? What did Louis de Broglie discover? Is light is a wave or it is a particle or both ?Let us know all these things..

Wave nature of light;

  

 The wave nature of light was well established by the end of the nineteenth

century. The phenomena of interference, diffraction and polarisation were explained

in a natural and satisfactory way by the wave picture of light. According to this

picture, light is an electromagnetic wave consisting of electric and magnetic fields

with continuous distribution of energy over the region of space over which the wave

is extended. But the wave picture of light is unable to explain the most basic features

of photoelectric emission.

Photoelectric effect thus gave the evidence to the strange fact that light in

interaction whit matter behaved as if it was made of quanta or packets of energy,

each of energy hv. Let us now know about…

Particle nature of light;

  

 Is the light quantum of energy associated with a particle? Einstein arrived at the

important result, that the light quantum can also be associated with

momentum(hv/c). A definite value of energy as well as momentum is a strong sign

that the light quantum can be associated with a particle. The particle was further ,

confirmed in 1924, by the experiment of A.H Compton (1892-1962) on scattering of

X-rays from electrons. In 1921 , Einstein was awarded the Noble Prize in Physics for

his contribution to theoretical physics and the photoelectric effect. In 1923, Millikan

was awarded the Noble Prize in physics for his work on the elementary charge of

electricity and on the photoelectric effect.

Dual nature of light;

 The dual nature of light comes out clearly from what we have learnt. The wave

nature of light shows up in the phenomena of interaction, diffraction and

polarisation. On the other hand, in photoelectric effect and Compton effect which

innvolve energy and momentum transfer, radiation behaves as if it is made up of a

bunch of particles - the photons.

    In 1924, the French physicist Louis Victor de Broglie (1892-1987) put forward the

bold hypothesis that moving particles of matter should display wave-like properties

under suitable conditions. He reasoned that nature was symmetrical character. If

radiation shows dual aspects, so should matter. De broglie proposed that the

wavelength associated with a particle of momentum p is given as ..

                        𝝺=h/p=h/mv