1785 – France

‘The force of attraction or repulsion between two charges is directly proportional to the product of the two charges and inversely proportional to the square of the distance between them’

The region around a charged object where it exerts a force is called its electric field. Another charged object placed in this field will have a force exerted on it. Coulomb’s rule is used to calculate this force.

Coulomb, a French physicist, made a detailed study of electrical attractions and repulsions between various charged bodies and concluded that electrical forces follow the same type of law as gravitation. Coulomb found a similar principle linking the relationship of magnetic forces. He believed electricity and magnetism, however, to be two separate ‘fluids’.
It was left to HANS CHRISTIAN OERSTED, ANDRE-MARIE AMPERE and MICHAEL FARADAY to enunciate the phenomenon of electromagnetism.

The SI unit of electric charge, coulomb (C), one unit of which is shifted when a current of one ampere flows for one second, is named in his honour.

He also articulated Coulomb’s rule of friction, which outlines a proportional relationship between friction and pressure.

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CARL GAUSS (1777-1855)

1832 – Germany

‘The electrical flux through a closed surface is proportional to the sum of the electric charges within the surface’

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An electric field may be pictured by drawing lines of force. The field is stronger where these lines crowd together, weaker where they are far apart. Electrical flux is a measure of the number of electric field lines passing through an area.

Gauss’ law describes the relationship between electric charge and electric field. It is an elegant restatement of COULOMB‘s law.


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