Coulomb's Law in Vector Form

Chapter-1|Electric Charges and Fields | NCERT 12th Physics:

Coulomb's Law in Vector Form:

We consider two positive charges q1 and q2 are placed in vacuum at a distance r from each other. They repel to each other.

According to Coulomb's law the magnitude of force on charge q1 due to q2 is given by

On comparing equation (I) and (II)

                       F₁₂ = - F₂₁

From above Coulomb's law agrees with Newton's third law.