Discovery of Electron Proton Neutron: Electric Discharge Through Gases: When an electric discharge is passed between two electrodes (by applying a potential of 10,000 volts or more) sealed in a glass tube (discharge tube) containing air at a very low pressure of 1 mm Hg, the electricity flows and the air between the electrodes begins to glow. Now if the air is replaced by any other gas, the glow still persists but its colour is different for different gases. It is reddish for air, orange-red for neon, bluish violet for hydrogen etc. On further lowering the pressure, the glow in … Continue reading Discovery of Electron Proton Neutron