 # What is the vectorial form and derivation of Coulomb`s law?

5 years ago
Dear student

Coulomb’s law: The electrostatic force between two stationary point charges is directly proportional to the product of their charges and inversely proportional to the square of the distance between them.

Vector form of Coulomb’s law: if ri and rj are position vectors of two point charges Qi and Qj and Fij is the force exerted by Qj on Qi, then

Fij=kQiQj(ri-rj)/[|ri-rj|]^3.

Importance of vector form: (1):Vector form gives the direction of the force along with magnitude.

(2) When we study force on a given charge by many charges, we use superposition principle. This principle states that electrostatic force on a given charge due to many charges is vector sum of individual forces due to other charges. When we consider effect due to one charge we ignore the presence of other charges. The force on charge 1 due to charges 2,3,…..N is ,according to superposition principle, is given by

F=F12+F13+……….F1N.

Regards