Properties of Cathode Rays

Cathode rays are the beam of electrons travelling from the negatively-charged cathode to the positively charged anode at the other end of the vacuum tube. These cathode rays travel in a straight-line path at high speed when a voltage difference is applied to the electrodes.

Cathode rays were discovered by Johann Hittorf in the year 1869. He used Crookes tubes and observed shadows cast on the glowing wall opposite the negative electrode in the tube.

J.J.Thomson discovered a new subatomic constituent of cathode rays in the year 1897. This subatomic particle was later named as electrons. He found that the mass of the particles on the cathode rays is 1800 times lighter than hydrogen, the lightest element. J.J Thomson was awarded the Nobel Prize in Physics for this work.

11 Important Properties of Cathode Rays

Property 1: Cathode rays travel in a straight line and can cast sharp shadows.

Property 2: Cathode rays are negatively charged.

Property 3: Electric field and magnetic field deflect cathode rays.

Property 4: They are produced at the cathode (negatively charged electrode) and travel towards the anode (positively charged electrode) in a vacuum tube.

Property 5: The properties of the cathode rays do not depend on the electrodes and the gas used in the vacuum tube.

Property 6: Speed of cathode rays is slower than light.

Property 7: The objects hit by cathode rays get heated.

Property 8: They can penetrate through thin metal plates.

Property 9: Phosphors glow when cathode rays fall on them.

Property 10: Gas gets ionized by cathode rays.

Property 11: Cathode rays are 180⁰ times lighter than hydrogen, the lightest element.