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Which type of electron emission requires a strong electric field to accelerate electrons to overcome potential barriers?

Option: 1

Photoelectric emission

Option: 2

Thermionic emission

Option: 3

Field emission

Option: 4

Secondary emission

Answers (1)


In photoelectric emission, electrons are emitted from a metallic surface when electromagnetic radiation of suitable frequency is incident on it. In thermionic emission, additional energy is given to the electrons in the form of heat to overcome the potential barrier. In secondary emission, the work function is supplied to the free electrons of a metal surface by collisions with fast-moving secondary particles.

Field emission, also known as cold emission, is a type of electron emission in which a strong electric field accelerates the electrons to such a high speed that they can overcome the potential barrier and be emitted from the metal surface. This process is used in a variety of applications, including vacuum tubes, flat-panel displays, and electron microscopes.

Therefore, the correct answer is option C, Field emission.

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