Write the complete explicit vector form of Coulomb's law.
Consider two charges q1 and q2. Let the position vectors of the respective charges be r1 and r2.
Let, the force acting on q1 due to q2 be F12 and the force acting on q2 due to q1 be F21.
The vector leading from 1 to 2 is denoted by r21 :
r21= r2 - r1
ly, vector leading from 2 to 1 is denoted by r12:
r12=r1 - r2
and
r12=-r21.
The direction of a vector is specified by a unit vector along the vector.
Now, Coulomb's force law between two point charges q1 and q2 when force is acting on q2 due to q1 is expressed as:
And, force acting on q1 due to q2 can be expressed as: