What are the properties of cathode rays?

What are the properties of cathode rays?

Aug 26, 2022, 16:45 IST

Properties of Cathode rays (W. Crooks, J. Plucker & J.J. Thomson):

1. They produce a sharp shadow of the solid object placed in their path. This show that cathode rays travel in straight lines.
2. If a light paddle wheel (e.g., that of mica mounted on an axle is placed in their path, the wheel begins to rotate. This shows that cathode rays are made up of material particles.
3. When an electric field is applied on the cathode rays, they are deflected towards the positive plate of the electric field. This shows that cathode rays carry negative charge. The negatively charged material particles constituting the cathode rays are called electrons.
4. When cathode rays strike a metal foil, the latter becomes hot. This indicates that cathode rays produce heating effect.
5. They cause ionization of the gas through which they pass.
6. They produce X-rays when they strike against the surface of hard metals like tungsten, molybdenum etc.
7. They produce green fluorescence on the glass walls of the discharge tube as well as on certain other substances such as zinc sulphide. e.g., Television picture tube.
8. They affect the photographic plates.
9. They possess penetrating effect (i.e., they can easily pass through thin foils of metals). They are stopped only by the metal foils of greater thickness.
10. The nature of the cathode rays does not depend upon the nature of the gas, taken in the discharge tube and the nature of cathode material.
11. For each negatively charged particles of cathode rays, the ratio of charge (e) to mass (m) is constant i.e., e/m = 1.76 x 10 ⁸ c/g = 1.76 x 10 ¹¹ c/kg. Thus the mass of cathode ray particle is 1837 times smaller than that of the H – atom.

Physics Wallah Chemistry Doubts page consist of more questions for reference.

What are the properties of cathode rays? pdf