1. The problem statement, all variables and given/known data When a -9.0 micro-coulomb charge is placed 0.12 cm from a charge q in a vacuum, the force between the 2 charges is 850 N. What is the value of q? 2. Relevant equations F = kq1q2/r2 3. The attempt at a solution q2 = Fr2/kq1 q2 = (850 N)(0.0012 m2)/(9.00 x 109 Nm2/C2)(-9.00 x 10-6 C) q2 = -1.22 x 10-18 C My question is am I doing this right? The answer that my book gives is 1.5 x 10-8 C.