Electric Field Electron Emission- Definition, Working, Methods, Uses & Applications

Electric field electron emission is the cycle by which free electrons are transmitted from the metal surface when solid electric field is applied.

Electric field electron emission is additionally called as electron field emission, field electron emission and field emission. Electric field electron emission happens in metals, yet in addition in liquids.

Field electron emission happens in metals that are put at extremely impressive electric field. As such, field electron emission happens when huge amount of energy as electric field is applied to the free electrons in the metals.

What is Electric field?

Electric field is the locale around a positively charged particle (proton) or negatively charged particle (electron) inside which other positively charged particle (proton) or negatively charged particle (electron) experience an attractive or repulsive force.

Protons have positive electric field or electric charge while electrons have negative electric charge. We realize that two inverse charges attract each other and same charges repulse each other. Protons and electrons have inverse charges or different charges. Consequently, when the electron is set in the electric field of a proton, it gets attracted to the proton.

Then again, two protons or two electrons have a similar charge. Thus, when one electron is set in the electric field of another electron, they create some distance from one another. Similarly, when one proton is set in the electric field of another proton, they get away from one another.

Metals in the absence of external electric field

Whenever no external electric field is applied to the metals, electrons can’t escape from the metals. However, some valence electrons in the metals become free from the parent atoms.

Under normal typical temperature, some valence electrons gain adequate energy from the heat and break the holding with the parent atom. The electron, what breaks the holding with the parent atom, moves freely from one region to another region inside the metal. These electrons are called as free electrons.

The free electrons moving from one region to another region have some kinetic energy. However, the free electrons don’t have adequate energy to escape from the metal surface. The solid attractive power of the nuclei prevents the free electrons, which attempt to escape from the metal.

The free electrons need adequate energy from the outer electric field to beat the attractive force of the nuclei. The free electron, which defeats the attractive force of the nuclei escape effectively from the metal surface.

Metals in the presence of external electric field

Whenever a solid positive electric field is applied to the metal, the free electrons in the metal experience an appealing force. These electrons acquires additional energy from the outside electric field.

Assuming the solid electric field applied to the metal is sufficiently incredible, the free electrons in the metal acquires sufficient energy and break the holding with metal or conquer the attractive force from the atomic nuclei. The free electrons what breaks the holding with the metal, will jumps into the vacuum.

Note- Electric field electron emission depends upon strength of the electric field and work function of the metal

The quantity of free electrons emissiond from the outer layer of metal depends upon the strength of the electric field applied to the metal and the work function of the metal.

Strength of the electric field

Assuming that strong solid electric field is applied to the metal, huge number of free electrons acquires adequate energy and beats the attractive force of the nuclei. The free electrons, which overcome the attractive force of the nuclei, will bounces into the vacuum.

Then again, assuming that weak electric field is applied to the metal, less number of free electrons gain adequate energy and overcomes the attractive force of the nuclei. The free electron, which defeats the overcomes the attractive force of the nuclei, will bounces into the vacuum.

Thus, the quantity of free electrons emitted from the metal surface increases with increase in the strength of the electric field. In this way, the free electrons emitted from the metal surface are directly proportional to the strength of the electric field.

Work function of a metal

The minimum external energy required to emit the free electrons from the outer layer of a metal is called function.

Metals with low work function require less electric field strength to emit free electrons from the metals. Then again, metals with high work function require high electric field strength to emit free electrons from the metals.

In this manner, the electron emission from the metal surface is inversely proportional to the work function of metal.

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