(b) State two applications of electrical conduction through gases.
(a) Thermionic emission: the emission (giving off) of electrons from the surface of a metal when it is heated to a high temperature. The heat gives the free surface electrons enough kinetic energy to overcome the work function (the surface attractive forces) and escape from the metal.
(b) Two applications of electrical conduction through gases:
Fluorescent tubes and neon/discharge advertising signs.
Sodium and mercury-vapour street lamps (the cathode-ray/television tube and lightning are also acceptable examples).
(a) Thermionic emission: the emission (giving off) of electrons from the surface of a metal when it is heated to a high temperature. The heat gives the free surface electrons enough kinetic energy to overcome the work function (the surface attractive forces) and escape from the metal.
(b) Two applications of electrical conduction through gases:
Fluorescent tubes and neon/discharge advertising signs.
Sodium and mercury-vapour street lamps (the cathode-ray/television tube and lightning are also acceptable examples).