In a diagram of electric field lines, q1 has 9 lines going into it and q2 has 27 lines going out of it. If one of

Question

In a diagram of electric field lines, q1 has 9 lines going into it and q2 has 27 lines going out of it. If one of 
the charges is -40 mC, which of the following could be the other one?

drwls · Accepted Answer

You offer no choices. The total E-field flux leaving a charge is proportional to the charge. (Gauss' law). The charge with field lines going in is negative. The other charge (with field lines going out) must be positive, and three times the magnitude, or 120 mC