Is Photon An Electron: Everything You Need to Know


A photon is a massless particle that does not exhibit mass but carries energy while the electrons are a negatively charged particle that has some mass. Let us discuss whether is photon an electron.

Though photon is generated as the electrons emit energy while transiting from higher to lower energy levels giving away the energy in the form of photons, the photon is not an electron but it can levy energy to the electron.

Can a photon become an electron?

A photon can definitely not become an electron but it can provide energy to the electron to jump from lower to higher energy levels.

If the energy of the photon is greater than the ionization energy of the atom then the incident photon can break the attraction between the electron and nucleus of an atom releasing the electron freely.

Losing the electron from the atom produces the ion and hence it is called the ionization process. The photon only imparts the energy to this escaping electron but it is not true that a photon is converted into an electron.

Are electrons made of photons?

It is said that the high-frequency photon emerged into the formation of electrons and plasma of quarks and gluons during the Big Bang.

The electrons producing the electromagnetic field emit photons giving away the energy gained by the field. The photons are created by the energy of the electron. As the electrons receive the energy they show electronic transitions emitting the extra energy.

The light in the universe is seen due to the photons traveling in the electromagnetic waves carrying the package of energy. This is due to the fission and fusion reaction seen by the electrons.

Is photon smaller than an electron?

The rest mass of a photon is nil but it moves with a speed equal to the speed of light while the rest mass of an electron is 9.1* 10-31k

A photon being is a massless particle move with high velocity and on contrary, the speed of the electron is low as compared to the photon propagating with huge energy.

The de Broglie wavelength of the photon is

The D’Broglie wavelength of the electron if velocity is approximately 0.9c then

The wavelength of the electron differs based on the atomic configuration and the energy gained by the electron. The greater the size of the atom, the smaller is its wavelength.

It is found that the wavelength of the electron is smaller than the photon. This is due to the fact that the electron is bigger than a photon.

Is photon emitted from an electron?

The electrons also react with the quark particles to produce protons and neutrons

A photon is given away by the electron as it jumps from the higher energy level to the lower energy state, giving its energy to the photon that is emitted.

The wavelength of the photon emitted is calculated using the formula

where R is Rydberg’s constant, Z is atomic no. and n1 and n2 are the orbital numbers in which the transition takes place.

Can a free electron emit a photon?

A free electron can emit a photon if the electron absorbs the energy in some form.

This electron can bind with some other particle as it is in free random motion and can emit the photon. Upon reacting with some other energized particle, it receives the extra energy which is emitted in the form of a photon.

If the photon is completely binding with the free electron then the speed of the electron can become equal to the speed of light.

Photon and Electron Interaction

A photon has ‘p’ and ‘E’ and if reacts with an electron we get a Compton scattering effect. As the incoming photon of wavelength λ incident on the electron, the part of its energy is given to the electron and is scattered back with low energy thus increasing its wavelength.

is photon an electron
Compton Scattering

This is a type of inelastic scattering because the wavelength of the light incident differs from the scattered light and also the energy decreases. This change in wavelength is given by the equation

where θ is an angle made by the scattered particle.

Secondly, the photon electron interaction can also be seen in the photoelectric effect. This effect takes place as the highly energized photons are made incident of the cluster of atoms.

If the electron acquires energy greater than its binding energy then it will dislocate it from the inner shell of the atom. This is now called a photoelectron.

Photoelectric effect; Image Credit: Wikipedia

The kinetic energy gained by the emitted photoelectron is equal to the energy of the photon minus the binding energy of the electron emitted. The emission of electrons from the inner shell of an atom creates a vacant space in the shell that is filled by the electron in the nearby shell.

The transition of an electron from higher to lower energy orbit implies that the energy of the electron has to be decreased and this energy is emitted giving away the photon producing the x-rays.

Photon and Electron Difference

Photon is a massless quanta of energy, its rest mass is zero while an electron has a mass of

. The photons travel at the speed of light while it is impossible for electrons to move with the speed of light.

Photon has no charge while electron we know is negatively charged. Photon shows more wave characters while electron shows more of the particle properties.

Photon is a package of energy and gains mass which is equal to E/c2 as it travels with the speed of light and has energy and momentum. The energy of the photon is converted into mass while propagating with the speed of light, hence it is found that it exhibits particle behavior too.

Photon and Electron Wavelength

The speed of the particle is directly proportional to its wavelength by the equation, v=fλ accordingly the wavelength of the photon has to be more than the electron.

If the photon and electron both have the energy of 1ev then what will be the difference in the wavelength of the both, let us calculate and understand the same.

The photon travels with the speed of light hence the energy of the photon can be measured using the equation,

E=pc because the energy of a photon is due to momentum term only.

Further we can write,

Where h is Planck’s constant, c is speed, and λp is the wavelength of the photon.

Hence, based on this we can measure the wavelength of the photon as

Now let us find the wavelength of an electron with energy 1eV.

The energy of the electron is

Since wavelength of the electron can be found using formula

Hence it is concluded that the wavelength of the photon is bigger than that of an electron.

Photon and Electron Mass

The photon though has the momentum it is a massless quanta of energy. As per the relativistic theory, the energy that the photon possesses is E=pc due to the momentum and when it is in motion the mass of the photon is equivalent to E/c2

The mass of the electron changes when it is in motion using kinetic energy. The relativistic mass of the electron in motion is

where

The mass of electron was calculated using Rydberg constant

where α is a fine structure constant measured from the spectroscopy

Thus we get the rest mass of electron using this equation

is found to be 9.1*10-31kg

Photon and Electron Energy

The energy of any particle is directly related to the frequency of its occurrence and is given by

E=hγ

Where h is a Planck’s constant and γ is a frequency.

γ=v/λ

Since, speed of the photon is equal to c, then

E=h/cλ

Depending upon the wavelength of the light, we can determine the energy associated with the photon emitting the light.

The energy of the electron varies depending upon the energy grasped by the electron to make the transition to a higher energy level or the total energy is given away to occupy a lower energy state than the existing one.

The momentum of the particle is conserved and the energy of the electron can be calculated using the formula E=p2/2m. As the electron jumps from one level to another, the energy lost or gained can be calculated by knowing the variation in the frequency of the electron ΔE=hγΔ

What is the ratio of the wavelength of electron and photon?

The wavelength of electron is λe=h/√2m/E while the ratio of photon is h/√2m/E

The ratio of the wavelength of electron and photon is equal to the square root of total energy by twice the mass of the electron times the inverse of the speed of the photon.

What is the wavelength of the electron having the energy of 0.511MeV?

Given: E=0.511MeV

m=9.1*10-31kg

We have,

The wavelength of the electron is 1.72pm.

Conclusion-

The photons are the packages of energy moving in the electromagnetic wave while the electron shows a duality in nature and has a mass. The transition of the electron from higher to lower energy levels gives out the photon carrying the extra energy emitted by the electron.

AKSHITA MAPARI

Hi, I’m Akshita Mapari. I have done M.Sc. in Physics. I have worked on projects like Numerical modeling of winds and waves during cyclone, Physics of toys and mechanized thrill machines in amusement park based on Classical Mechanics. I have pursued a course on Arduino and have accomplished some mini projects on Arduino UNO. I always like to explore new zones in the field of science. I personally believe that learning is more enthusiastic when learnt with creativity. Apart from this, I like to read, travel, strumming on guitar, identifying rocks and strata, photography and playing chess. Connect me on LinkedIn - linkedin.com/in/akshita-mapari-b38a68122

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