Point charges q1 = 2.0 µc and q2 = 4.0 µc are located at →r 1 = (4.0 i ^ − 2.0 j ^ + 5.0k ^ )m and →r 2 = (8.0 i ^ + 5.0 j ^ − 9.0k ^ )m . what is the force of q2 on q1 ?

Given two point charges and which are a distance apart.

The force on one of the charges is proportional to the magnitude of its own charge and inversely proportional to the square of the distance between them.
i.e.


where is the constant of proportionality

Given that and

Also, given that m and m, then



Therefore, the force of on is given by