CATHODE RAYS AND DISCOVERY OF ELECTRON

Source:  CATHODE RAYS AND DISCOVERY OF ELECTRON    Tag:  cathode ray discharge tube experiment
In 1895 Sir William Crooks performed experiments by passing electric current through gases in a discharge tube st very low pressure.
        He took a glass fitted with two metallic electrode,which were connected to a high voltage battery.The pressure inside the tube was kept 10 raised to power -4 atm.When high voltage current was passed through the gas,shiny rays were emitted from the cathode which travel towards the anode.These rays were given the name of 'cathode rays' as these were originated from the cathode.

PROPERTIES OF RAYS
1:These rays travel in straight lines perpendicular to the cathode surface.
2:They can cast a sharp shadow of an opaque object if placed in their path.
3:They are deflected towards positive plate in an electric field showing that they are negatively charged.
4:They raise temperature of the body on which they fall.
5:J.J.Thomson discovered their charge/mass(e/m)ratio.
6:Light is produced when these rays hit the walls of the discharge tube.
7:It was found that the same  type of rays were emitted no matter which gas and which cathode was used in the discharge tube.

ELECTRONS
       These rays cast the shadow of an opaque object suggested that these are not rays but they are fast moving material particles.They were given the name of 'ELECTRONS'.
     Since all the materials produce same type of particles,it means that all the materials contain electrons.

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