In some discharge lamps the work function of the metal catho

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^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 which are needed to make sense of what\'s going on.

Solution

Answer:

A gas discharge tube is a bulb or tube (usually glass), with two (or more) electrodes inserted into it, that has been evacuated and filled with a gas or gas mixture usually at somewhat less than atmospheric pressure. All such tubes have the property that, as the voltage applied across the electrodes is increased, there comes a point called the \'strike voltage\' or \'breakdown voltage\', at which any localised ionisation of the gas will initiate an avalanche process that spreads through the tube. The voltage at which breakdown occurs depends on the composition and pressure of the gas mixture and the strength of the applied electric field according to a relationship known as \'Paschen\'s law\'.

The basic discharge process always follows three steps:

Joule heating of the filament to overcome the work fuction of metal, in order make electrons free. This is done by sending the current in filament.

Heat produced = I²Rt

Now these free electrons are accelerated via applying the field

energy acquired by electron = eV

Now these accelerated electrons ionise the atoms which in turns give radiation via excitation of electron in an atom.