What did J. J Thomson experiments with cathode ray tubes imply about he mass of an electron?

By firing electrons from a cathode gun at a known velocity through an electric field of a known strength, J. J Thomson was able to observe how much the field deflected the beam. With a mass-to-charge ratio calculated, he could determine that the mass of the electron was not significantly heavy (in fact almost nothing compared to the proton or neutron)

J. J. Thomson carried out an experiment in which he find the charge to mass ratio of electron.

Explanation:

J. J. Thomson carried out an experiment in which he used cathode rays which are emitted from cathode gun. Later it was proved that the cathode rays which are emitted from cathode gun were actually a beam of negatively charged particles which are known as electrons.

when these cathode rays passes through an electric field these rays get attracted towards the positively charged plate and get repelled by negatively charged plate of electric field. In this way these rays get deflected from its path and by measuring, how much cathode rays get deflected from its path J. J. Thomson was able to determine mass to charge ratio.

Thomson carried out the experiment by using different types of cathode which are made from different types of metal and he also filled different gases in the discharge tube but every time he got same charge to mass ratio. After repeating the experiment with different types of cathode and different gases, J. J. Thomson concluded that the cathode ray beam is actually consist of negatively charged particle which is a universal component of matter and which is known as electron. He observed that electron has fixed mass.