An arrangement of 3 charges is drawn showing the field lines. The first charge has 20 lines going into it. The second charge has 30 lines going out of it. If the net charge of the arrangement is zero, what is the field line situation for the third charge?
A) 50 lines going out
B) 50 lines going in
C) 10 lines going out
D) 10 lines going in
E) 600 lines going out to infinity

Question

Quizplus · Accepted Answer

The net charge is zero, so the total number of lines going in must equal the total number of lines going out. With 20 lines going into the first charge and 30 lines going out of the second charge, the third charge must have 10 lines going in to balance the field lines.

An Arrangement of 3 Charges Is Drawn Showing the Field