Question

discovery of electrons

Answer 1

Electron was discovered by J. J. Thomson in 1897 when he was studying the properties of cathode ray. Figure 1. J. J. Thomson won Nobel Prize in 1906 for discovering the elementary particle electron.

Answer 2

$\huge\mathfrak{A{\textbf{\red{nswer :}}}}$


$\textbf{DISCOVERY OF ELECTRON}$

→ It is fact that gas is a poor conductor of electricity, but if it's pressure is reduced then the electricity starts flowing through the gas.

→ For this experiment requirements are :-

* Discharge tube; made up of hard glass 55 cm length.

* Two metal electrodes.

* A vacuum pump (to reduce pressure of gas)

$\textbf{OBSERVATIONS}$

→ Under normal condition (1 atm) = No observation.

→ Under reduced pressure (10-² atm) = Gas emit light.

→ Under reduced pressure (10-⁴ atm) = Greenish light (Fluorescence)

* Rays emitted from cathode are called cathode Rays. When these rays strike or bombard to the glass walls of tube, then fluorescence is produced. These rays consists of negatively charged particles.

$\textbf{PROPERTIES}$

→ Cathode rays start from cathode and move towards anode.

→ Cathode rays travel in straight line. If any object is placed in between there path, then the shadow of the object is formed 

→ Rays themselves are not visible but they can be visible by their lightening effect called fluorescence.

→ Rays are made up of the material particles. So, they can rotate a light weight particle placed in their path.

→ Formation of shadow represents wave nature of cathode rays.

→ When any electric or magnetic field is applied then the rays behave as negatively charged particles shows that these rays are electrons.

$\textbf{J.J. Thomson}$ in 1897 discovered the electron.

* Diagram is in Attachment !!

=====================================