Two point charges q1 = -6.15 nC, and q2 = -10.5 nC are separated by 25.0 cm (see figure below).
(a) Find the net electric field these charges produce at point A
(b) Find the net electric field these charges produce at point B
(c) What would be the magnitude and direction of the electric force this combination of charges would produce on a proton at A?
The Attempt at a Solution
I got the correct answer for (b), but got an incorrect answer for (a) using the same method.
E = (ke*Q)/(r2)
ƩE = 9*109 * [(6.15*10-9)/(0.152) + (10.5*10-9)/(0.102)] = 11910 N/C to the right