Positive Rays:
In 1886, Eugen Goldstein used a discharge tube with a hole in the cathode. He observed that while cathode rays were streaming away from the cathode, there were coloured rays produced simultaneously which passed through the perforated cathode and caused a glow on the wall opposite to the anode. Thomson studied these rays and showed that they consisted of particles carrying a positive charge. He called them positive rays.
Properties of Positive Rays:
Some of the important properties of anode rays are as follows-
- They travel in a straight line in a direction opposite to the cathode.
- They are deflected by electric as well as magnetic field in a way indicating that they are positively charged.
- The charge to mass ratio (e/m) of positive particles varies with the nature of the gas placed in the discharged tube.
- They cause fluorescence in the zinc sulphide.
It was J.J. Thomson who studied their nature and found that the actual mass of proton is +1.60 X 10-19 C and has mass equal to that of hydrogen atom. Therefore, “A proton is a subatomic particle which has one unit mass and one unit positive charge i.e. +1.60 X 10-19 C”.