Discovery of Electron, Proton and Neutron-Properties of Anode Rays

• Anode rays, positive rays, or canal rays are defined as beams of positively charged particles.
• The renowned scientist Goldstein conducted a discharge tube experiment with a perforated cathode in 1886.
• He noticed that, in addition to cathode rays, a new type of ray was discovered.
• Though these rays passed through the perforated cathode hole, they travelled in the direction opposite to the cathode rays.
• These rays, which were discovered to be made up of positively charged particles, were given the name anode rays, positive rays, or canal rays.
• The Anode rays are produced as a result of the bombardment of high-speed electrons from cathode rays on gaseous atoms, which knocks electrons out of them.

Production of the Anode rays

• When the electrons that are emitted from the cathode collide with gas atoms that are present in the tube, they knock one or two extra electrons out from these atoms.
• As a result of these collisions, positively charged ions are left behind.
• These positively charged ions move towards the cathode and when they pass through the perforations in the cathode disc, canal or anode rays are created.
• These anode rays are deflected in the same direction from the cathode rays by both the electric and magnetic fields. The behaviour of the anode ray particles in an electric and magnetic field was different from that of cathode rays.
• As the anode rays are made of the positive ionised ions which are formed by the ionisation of the gas present in the tube, anode rays are dependent upon the nature of the gas which is present in the glass tube.
• In the case of the Anode rays, the charge to mass ratio for the particles of the ray is different for the different gases.

Properties of the Anode rays

The properties of the Anode rays can be listed as below :

• The anode rays consist of positively charged particles. The mass of anode rays is almost identical to the atoms from which they are derived. Their mass is also equal to the atomic mass of the gas which is present in the tube.
•  Anode rays travel in straight lines.
• The anode rays have the potential of producing physical as well as chemical changes.
• The anode rays possess the ability to penetrate thin metal foils.
• The anode rays can also produce the effect of ionisation in gases.
• The anode rays are also deflected by the electrical and magnetic fields but their deflection is in a direction that is opposite to the cathode rays proving that they are charged opposite to the cathode rays i.e positively.
• Since the deflection of the anode rays is little , it points out that their particles are very heavy.

Differences between the Cathode and Anode rays

The cathode and anode rays are different from each other in terms of the following aspects: –

• Cathode rays are negatively charged particles whereas the anode rays are positively charged in nature.
• While passing through the electric field the cathode rays bend towards the anode whereas the anode rays bend towards the cathode.
• The e/m ratio in case of cathode rays is same for all gases whereas in case of the anode rays it is different for all gases.
• The negatively charged particles emitted from a cathode ray are called electrons whereas the positively charged particles from the anode are called as H+ ions.

Conclusion

Anode rays are  radiations that are positively charged and made up of particles with charges that are equal in magnitude but reverse in sign to the electron’s. They can also be described as a beam of positive ions produced by certain types of gas discharge tubes. An anode ray particle has a mass which is equal to 2000 times of an electron. This particle is referred to as a proton.