Question

The type of electron emission wherein a very strong electric field applied to the metal pulls the electrons out of the metal surface is called
1. Thermionic emission
2. Field emission
3. Photoelectric emission
4. None of the above

Answer 1

Correct Answer - Option 2 : Field emission

The correct answer is option 2) i.e. Field emission

CONCEPT:

• Electron emission: It is the phenomenon when electrons escape from a metal surface. There are three types of electron emission.
  1. Thermionic Emission: It is the process in which the electrons are ejected from a metal surface when the metal is heated to a sufficient temperature.
  2. Field Emission: It is the process in which electrons are pulled out of the metal surface due to a very strong electric field.
  3. Photoelectric effect: The photoelectric effect is a phenomenon where electrons are ejected from a metal surface when the light of sufficient frequency is incident on it.

EXPLANATION:

• ​Electrons emitted due to the electric field applied to a metal surface is a result of field emission. Therefore, the correct answer is field emission.