Dual Nature of Light

We all are familiar with light.

Suppose we have three cardboards having three pin holes in them.

Now we place a candle on one side of the cardboard and try to look from the other side.

If the candle flame and the cardboard holes are in a straight line, we can see the flame.

If anyone of them is not in a straight line, the flame is not visible and hence we can say that the light travels in a straight line.

This can be explained by considering light as a bundle of particles.

Now, let's take another example for light.

Suppose we put a straw into the glass of water. Then we will see the straw seems to move to the side.

It happens due to the refraction of light.

And refraction is phenomena of a wave. So, the light behaves like wave also.

Means the light is having dual nature.

Let's discuss the dual nature of light.

Light can act as a wave and it can also act as a particle.

Huygen was the scientist, who successfully explain the light is a wave.

And it is called as a huygen wave theory.

Huygen successfully explained the phenomena like reflection, refraction, interference, etc. by considering light as a wave.

However, the scientists made an attempt to explain the phenomena of the photoelectric effect and Compton effect.

They were not able to explain these phenomena by considering the light as a wave.

Later, Albert Einstein successfully explained the photoelectric effect by considering light as a particle.

He used a theory whose name was Planck's quantum theory.

According to Planck's quantum theory, light is a discrete packet of energy.

And this discrete packet of energy is called as photons.

And the energy () of a photon is calculated as,

Hence, the light is having a particle as well as a wave nature.

Revision

Light can act as a wave and it can also act as a particle.

Huygen was the scientist, who successfully explain the light is a wave.

Later, Albert Einstein used Planck's quantum theory to explain the photoelectric effect.

Hence, the light is having a particle as well as a wave nature.

The End