1)It consist of a long cylindrical tube sealed at both ends and is fitted with two metal electrodes.
2)The electrodes are connected to source of high voltage.
3)The tube is connected to a vacuum pump as to increase or decrease the pressure.
4)The discharge tube is filled with air.
He passed electricity at high voltage through a gas at very low pressure taken in discharge tube.
1)When the voltage is high and pressure is 1 atm,no electricity could flow through air.
2)The absolute mass of electron is 9.1 x 10-31 kg .