Particle Nature of Light – Laws of Photoelectric effect

Light is known to exist in two forms – particle and wave. In this article, you will find information regarding the particle nature of light. In 1900, scientist Albert Einstein found that when the light was allowed to fall on specific types of metals, electrons were ejected.

The energy was allowed to come in packets, also known as quanta or photons. This experiment laid the foundation for many other experiments. It was found that metals behave differently with lights of different wavelengths. Another factor that influenced this experiment was the intensity of the light. The intensity of the light also had a huge impact on the metals ejecting electrons.

All of these observations led to the discovery of another nature of light, which was assumed to be non-existing – particle nature. Earlier, scientists assumed it to be of the waveform. 

Particle nature of light

Before 1900, there was a myth that light only existed in the waveform. However, the myth was busted after the discovery of the particle nature of light. With it, it was clear that there were small packets of energy. These packets of energy were termed photons. Albert Einstein was also awarded the Nobel Prize for this discovery.

Examples of photon

Some of the best examples of photons are given below: 

• The conversion of particles into light and energy due to the sun is an example of photons. 
• The carrier of the electromagnetic force is also a photon. 

Characteristics of photons

Photons are nothing, just packets of light. You must have seen small packets which are sometimes filled with candies. In the same way, photons are small packets but instead of candies, there is energy. Here are the characteristics of photons: 

• Photon is a form of energy. 
• Photon does not have any mass.
• Photon does not carry any charge. 
• A photon always travels at the speed of light. 

What is the photoelectric effect?

When you bombard light on a specific metal, electrons are ejected. These ejected electrons are called photons and this phenomenon is known as the photoelectric effect. If the frequency of light is low, no electrons are ejected. But if the frequency of the electrons is high, a considerable amount of electrons is ejected. Conclusions were made after these observations.

Light and its features

• Light is made up of particles.
• The more the frequency of the particle, the more will be the energy of the particle.
• Only one electron receives the particle energy. 

Laws of the photoelectric effect

Given below are the laws of the photoelectric effect: 

• There should be no time lag between the incident of light and the emission of electrons. 
• The determination of kinetic energy is decided by the frequency of the incident light on the metal. 
• The number of electrons emitted by the metal is directly proportional to the intensity of the given light. 
• No electrons can be ejected before the cut-off frequency of the incident light. 

Dual nature of light

After the discovery of the particle nature of light, it brought a breakthrough in sciences and technology. Later, it was proved that light exists both as a particle and waveform. There are different applications of different nature of light. 

Application of particle nature of light

• The particle nature of light is used in Young’s double-slit experiment. In this experiment, the light was allowed to pass through a single slit and patterns were observed. 
• One of the most famous applications of the particle nature of light is the photoelectric effect, in which light is allowed to bombard specific metals, which release electrons in return.

Applications of wave nature of light

• The most famous example of the wave nature of light is interference, in which you will observe the interference patterns. 
• Another most popular example is that of diffraction. The light gets reflected due to uneven sources and forms various diffraction patterns. 

Conclusion

With the help of this blog, you will get to know about the photoelectric effect and photons. Photons play a major role in classical chemistry. Every light which you experience in daily life consists of lots of photons, which are also known as quanta or packets of energy.