How Does Gauss's Law Explain Net Flux in Electric Fields?

[jaejoon89]

A figure showing electric field lines has two charges, q and -q. There are 24 lines emanating from the +q charge. 15 of these lines terminate at -q. There are 24 lines terminating at the q- charge. What is the net flux through the surface surrounding the two charges?

 

[jaejoon89]

Well it is a dipole with the two charges being of equal magnitude, so wouldn't the net flux be 0?

 

[Defennder]

It's a closed surface right? Then just apply Gauss law. A more "conceptual" approach is to count how many lines are entering the closed surface and how many are exiting. Then find the net number of lines exiting the surface.