In some discharge lamps, the work function of the metal cathode is overcome by h

Question

In some discharge lamps, the work function of the
metal cathode is overcome by heating the electrons so they have enough thermal energy
to get out. The voltage difference across the plates then give these electrons a certain
amount of electrostatic potential energy. As always, energy must be conserved. Track
and explain the transfers and conversions between different forms of energy that occur
in a discharge lamp that make it work to produce light. Be sure to include the main
physics ideas about how atoms behave. Note that a single electron can hit multiple
electrons. PLEASE EXPLAIN. THANKS.

Explanation / Answer

Thermionic emission is the heat-induced flow of charge carriers from a surface or over a potential-energy barrier. This occurs because the thermal energy given to the carrier overcomes the binding potential, also known as work function of the metal. The charge carriers can be electrons or ions, and in older literature are sometimes referred to as "thermions". After emission, a charge will initially be left behind in the emitting region that is equal in magnitude and opposite in sign to the total charge emitted. But if the emitter is connected to a battery, then this charge left behind will be neutralized by charge supplied by the battery, as the emitted charge carriers move away from the emitter, and finally the emitter will be in the same state as it was before emission. The thermionic emission of electrons is also known as thermal electron emission. The classical example of thermionic emission is the emission of electrons from a hot cathode, into a vacuum (also known as the Edison effect) in a vacuum tube. The hot cathode can be a metal filament, a coated metal filament, or a separate structure of metal or carbides or borides of transition metals. Vacuum emission from metals tends to become significant only for temperatures over 1000 K. The conversion between electrical energy to kinetic energy of the electrons take place in this process

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