Discovery of Electron, Protons, And Neutron

  • Electron:

Long tome ago in 1859, WilliamsCrookes and juliusplucker started the study of conduction of electricity through gases at low pressure in discharge tube. After that in 1897,

The J. J. Thomson’s used a cathode ray tube to deduced the presence of negatively charged particle that is electron.

Experiment:

  • ray tube pass electricity through a gas that is contained at very low pressure.
  • Cathode rays cause green fluorescence on glass surface that is the glass surface on which the cathode rays strike and show colour shine.
  • These rays produce heat energy when they colloid with the matter .
  • It show that cathode ray posses kinetic energy which is converted into heat energy when stopped by matter.
  • These rays affect the photographic plate.
  • Cathode ray can penetrate the thin foil of solid material.
  • Cathode rays can ionize the gas through which they pass
  • The electrical discharge through gases could be observed at very low pressure and very high voltage.
  • When sufficient high voltage is applied across electrode .
  • Stream of particle start flowing from negative electrode to positive electrode.
  • They were name as cathode rays.
  • Charge of electron is taken to be -1. 6×10-19c .
  • Mass of electron is negligible that is [1/1837 times that of protons].

 

  • Proton

The discovery of positive charge particle was conducted by Goldstein in 1886. He used to perforated cathode in the modified cathode ray tube.

Experiment:

  • He used modified cathode ray tube and he was observed thatwhen high potential was applied between the electrode , not only cathode rays were produced but also new types of rays were  produce simultaneously from anode movie toward cathode..
  • These were name as canal rays since these pass through the canal of the cathode . These were also name as anode rays Because these originated from anode.
  • Charge of electron is taken to be 1. 6×10-19c .
  • Mass of protons is approximately1837 times that of electron.

 

  • Neutron

The discovery neutral particle that is they are neither positive nor negative In 1932by James Chadwick , these particle said neutron particle which is present inside the nucleus of atom.

Experiment:

  • James Chadwick bombarded a thin sheet of Beryllium by fast moving alpha particles.
  • As a result, he observed that certain neutral particles are emerging out.
  • These neutral particle were name as neutron.
  • Neutron are not deflected by electric or magnetic field.
  • Relative mass of neutron is 1u.
  • Atom of a elements contain neutron except ordinary hydrogen atom.

Question Answer:

1) Who discovered the electron?

Answer:J. J. Thomson discovered the electron.

2) Explain the experiment of electron or cathode ray tube?

Answer: Experiment:

  • Ray tube pass electricity through a gas that is contained at very low pressure.
  • Cathode rays cause green fluorescence on glass surface that is the glass surface on which the cathode rays strike and show colour shine.
  • These rays produce heat energy when they colloid with the matter .
  • It show that cathode ray posses kinetic energy which is converted into heat energy when stopped by matter.
  • These rays affect the photographic plate.
  • Cathode ray can penetrate the thin foil of solid material.
  • Cathode rays can ionize the gas through which they pass
  • The electrical discharge through gases could be observed at very low pressure and very high voltage.
  • When sufficient high voltage is applied across electrode .
  • Stream of particle start flowing from negative electrode to positive electrode.
  • They were name as cathode rays.

3) Who discovered the protons?

Answer: The discovery of positive charge particle was conducted by Goldstein in 1886.

4) Explain the properties of canal rays?

Answer: Properties of canal rays:

  1. They travel in direction opposite to the cathode rays.
  2. Anode rays are positive charge.
  3. These rays produce flash of light on ZnS screen.
  4. Anode rays also affected photographic plate.
  5. These rays can pass through thin metal foil.
  6. These can produce ionization in gas.
  7. Like cathode rays these rays also rotate the wheel places in their path and also have heating effect.
  8. These rays are deflected by electric and magnetic field in direction opposite to that of cathode rays.

5) Who discovered the neutron?

Answer:The discovery neutral particle that is they are neither positive nor negative  In 1932 by James Chadwick

6) Explain the discovery experiment of neutron?

Answer: Experiment:

  • James Chadwick bombarded a thin sheet of Beryllium by fast moving alpha particles.
  • As a result, he observed that certain neutral particles are emerging out.
  • These neutral particle were name as neutron.
  • Neutron are not deflected by electric or magnetic field.
  • Relative mass of neutron is 1u.
  • Atom of a elements contain neutron except ordinary hydrogen atom.

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