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)/(4piepsilon_(0))(q_(1)q_(2))/(r^(2) hatr_(21)`
Here `hatr_(21)` is unit vector from charge `q_(2)` to `q_(1)`
But `hatr_(21) = -hatr_(12),`
`vecF_(12)=(1)/(4piepsilon_(0))=(1)/(4piepsilon_(0))(q_(1)q_(2))/(r^(2))(-hatr_(12))=(1)/(4piepsilon_(0))(q_(1)q_(2))/(r^(2))(hatr_(12)) "or" vecF_(12)=-vecF_(21)`
Therefore the electrostatic force obeys Newton .s third law .