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? A) −120 mC B) 18.0 mC C) −18.0 mC D) 120 mC E) none of these choices are correct

Question

Quizplus · Accepted Answer

The number of lines is proportional to the magnitude of the charge. Since one charge has 9 lines (indicating a smaller magnitude) and the other has 27 lines (indicating a larger magnitude, three times as many), the charges must have magnitudes in a 1:3 ratio. If one charge is -40 mC, the other must be three times larger in magnitude but positive (since lines go out of it), making it 120 mC.

In a Diagram of Electric Field Lines, Q1 Has 9

In a Diagram of Electric Field Lines, Q₁ Has 9