Homework Help: Electric field strength

1. Jul 21, 2017

Cici2017

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution
I tried to use the formula: F=kq1q2/r2
So at point B, the electric field strength is( 2kQ/r2) - (-kQ/r2)= 3kQ/r2
At A: (2kQ/r2)+(-kQ/r2)=kQ/r2
At C: -(2kQ/r2)-(-kQ/r2)=-kQ/r2
So B is the strongest?
Is there an easier way to do it?

2. Jul 22, 2017

haruspex

B is the only one where the two fields reinforce, so it is a good candidate. It could only lose to A or C if those were significantly closer to one of the charges.