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Why is it that the electric field is pointing in the direction of the -8.0 micro Coulomb charge?
Hi honickb, you have to image which direction a positive charge would move if you dropped it into the picture. If you introduced a new positive charge, it would tend to move away from existing positive charges, and towards negative charges.
Electrice fields always point in the direction of force that would apply on a newly introduced positive charge. Textbooks say the electric field points in the direction of force on "an infinitesimally small positive test charge", and without the fancy words, I'm saying the same thing.