Discovery of Proton Experiment 2022
In 1896, a German physicist. Eugen Goldstein discovered another type of ray called positive rays or canal ass in the gas discharge tube.
Eugen Goldstein used a perforated cathode in the discharge tube. When a large voltage is applied, a glow appears on the glass wall opposite to the anode It is because some rays travel opposite to the cathode rays, and after passing through the perforated cathode, they produce a glow on the wall.
Since these rays pass through the holes (canals) in the cathode, these are called canal rays. These rays are called positive rays since they carry a positive charge.
How Canal Rays are Produced? (Origin of Positive Rays)
These rays are produced when high-speed cathode rays (electrons) strike the gas molecules present inside the gas discharge tube. Cathode rays remove electrons from the gas molecules and convert them into positive ions. These ions then move towards the cathode as a positive ray.
Properties of positive rays.
1. Travel in a straight line
Positive rays travel in straight line in a direction opposite to the cathode rays.
2. Produce flash.
They produce flash in on striking ZnS plate.
3. Positively Charged
These rays are deflected in an electric and magnetic field in a way that shows their positive charge
4. Charge to mass (e/m) ratio cathode
• The charge to mass ratio (e/m) for these rays is always smaller than for electrons.
• The e / m ratio depends upon the gas used in the gas discharge tube. The heavier the gas, the smaller the e / m value.
• The e / m ratio is highest when hydrogen is present. It is because the positive particle obtained from hydrogen has the least ‘m’ value. Hence its e/m ratio is the highest.
Conclusions of Discovery of Proton
Hydrogen produces the lightest positive particle. Rutherford called this positive particle a proton. It is also considered the fundamental particle of an atom.
• From e / m ratio of proton, the mass of proton was calculated to be 1.6726 x 10-27kg or 1.0073 amu
• The mass of the proton is 1836 times greater than that of the electron. FAC Protons and Electrons were discovered in 1886 and their properties were understood entirely until 1895.