Question

(b) How cathode rays are formed from the gas taken in the discharge tube?

Answer 1

Cathode rays:

1. J.J. Thomson performed an experiment with cathode ray discharge tube which consists of metal electrodes on either ends.
2. Electrode connected to negative terminal of battery is cathode and electrode connected to positive terminal is anode.
3. The tube is connected to a vacuum pump to control the pressure of gas in the tube.
4. Electricity is passed through the tube and radiations were observed to be emitted from cathode to anode.
5. These rays emitted from cathode are known as cathode rays.

Formation of cathode rays from the gas in the discharge tube:

1. When electricity is is passed through the tube, the gas in the tube gets ionized.
2. The ions then collide with the cathode and release electrons.
3. These electrons travel from cathode to anode.
4. Electrons are the cathode rays as they travel from cathode to anode.