Thermionic Emission Quiz

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Questions and Answers

What is thermionic emission?

Thermionic emission is the liberation of electrons from an electrode by virtue of its temperature.

What overcomes the work function of the material in thermionic emission?

The thermal energy given to the charge carrier overcomes the work function of the material in thermionic emission.

What classical example illustrates thermionic emission?

The classical example of thermionic emission is that of electrons from a hot cathode into a vacuum in a vacuum tube.

When does vacuum emission from metals tend to become significant?

<p>Vacuum emission from metals tends to become significant only for temperatures over 1,000 K (730 C; 1,340 F).</p> Signup and view all the answers

What is left behind in the emitting region after thermionic emission?

<p>After emission, a charge that is equal in magnitude and opposite in sign to the total charge emitted is initially left behind in the emitting region.</p> Signup and view all the answers

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Study Notes

Thermionic Emission

Thermionic emission is the process by which heated materials emit electrons into a vacuum.
The work function of the material is overcome by the thermal energy gained by the electrons due to heating.
A classical example of thermionic emission is the filament of an incandescent light bulb, which emits electrons when heated.
Vacuum emission from metals tends to become significant at temperatures above 1000°C.
After thermionic emission, positively charged ions are left behind in the emitting region.