Question

Hy guys :)
Give me a note about the discovery of mass ( me ) , charge ( e ) and charge by mass ratio of electron ( e/m )
p.s - Include the names of scientists who had discovered it , the year they discovered and values of each ( not approximate value )
Thanks in advance :D

Answer 1

in 1897,british physicist jj thomson measured the ratio of electrical charge 'e' to the mass of electron 'me' by using cathode ray tube and applying electrical and magnetic field perpendicular to each other as to the path of electrons...
e/me = 1.758820 * 10^11

e discovered by r a milkan by oil drop experiment to determine the charge of electron(1906-14)  =1.6022*10^-19
me discovered by jj thomson (1897) =9.1094 * 10^-31

Answer 2

J.J. Thomson's experiment and the charge-to-mass ratio of the electron

The first is the experiment of Joseph John Thomson, who first demonstrated that atoms are actually composed of aggregates of charged particles. Prior to his work, it was believed that atoms were the fundamental building blocks of matter. The first evidence contrary to this notion came when people began studying the properties of atoms in large electric fields.

Beam of electrons moving in a circle in a Teltron tube, due to the presence of a magnetic field. Purple light is emitted along the electron path, due to the electrons colliding with gas molecules in the bulb. The mass-to-charge ratio of the electron can be measured in this apparatus by comparing the radius of the purple circle, the strength of the magnetic field, and the voltage on the electron gun. The mass and charge cannot be separately measured this way—only their ratio.

If a gas sample is introduced into the region between two charged plates, a current flow can be observed, suggesting that the atoms have been broken down into charged constituents. The source of these charged particles is a heated cathode that, in fact, causes the atoms of the sample to ionize. These were known as cathode rays. In 1897, Thomson set out to prove that the cathode rays produced from the cathode were actually a stream of negatively charged particles called electrons. (See Figure 1.8 in the textbook for Thomson's experimental setup). From Maxwell's theory, he knew that charged particles could be deflected in a magnetic field. A schematic of the experimental setup