Write down Coulomb 's law in vector form and mention what each term represents .

Explanation

The force on a charge `q_1` exerted by a point charge `q_2` is given by `vecF_(12)=(1)/(4pi epsi_(0))=(q_(1)q_(2))/(r^(2)) hatr_(21)`
Here, `hati_(21)` is the unit vector from charge `q_(2)" to "q_(1)`.
But `hati_(21)=-hatr_(12)`
`vecF_(12)=(1)/(4piepsi_(0)) (q_(1)q_(2))/(4pi epsi_(0)) (-hatr_(12))=-(1)/(4piepsi_(0)) (q_(1)q_(2))/(r^(2)) (hatr_(12)) or vecF_(12)=-vecF_(21)`
Therefore, the electrostatic force obeys Newton.s third law.