(b) State two applications of electrical conduction through gases.
(a) Diffusion
Diffusion is the gradual movement or spreading of the molecules of a substance from a region of higher concentration to a region of lower concentration until the molecules are uniformly distributed. It occurs because the molecules are in continuous random motion, and it is faster in gases than in liquids because gas molecules move faster and are farther apart.
(b) Two applications of electrical conduction through gases
Fluorescent tubes and neon (discharge) lamps - light is produced when an electric current is passed through a gas at low pressure.
Advertising / sodium and mercury vapour street lamps - conduction through the vapour produces the characteristic coloured light used in signs and lighting.
(Other acceptable examples: the cathode-ray tube / X-ray tube, and the lightning discharge, which is conduction through air.)
Diffusion is the gradual movement or spreading of the molecules of a substance from a region of higher concentration to a region of lower concentration until the molecules are uniformly distributed. It occurs because the molecules are in continuous random motion, and it is faster in gases than in liquids because gas molecules move faster and are farther apart.
(b) Two applications of electrical conduction through gases
Fluorescent tubes and neon (discharge) lamps - light is produced when an electric current is passed through a gas at low pressure.
Advertising / sodium and mercury vapour street lamps - conduction through the vapour produces the characteristic coloured light used in signs and lighting.
(Other acceptable examples: the cathode-ray tube / X-ray tube, and the lightning discharge, which is conduction through air.)