22_1?Review May?2016 M.?Burkardt?? NMSU?? PHYS?214?? Spring?2016 1 Phys214 Electricity & Magnetism Review part 1 Fields and Sources of Fields Point Charges as Sources of Electric Field Review q? q? ?P How do you determine the electric field (direction and magnitude) at point P? d a Electric Dipole Shown is only a ?slice? through a 3-dim. electrical field. Note: The number of lines leaving the positive charge equals the number terminating at the negative charge. Electric fields of separate charges add as vectors. Gauss?s Law Surface Integral of Electric Field enc 0 Qd ?? E A ?? ?? ? If net charge Q is enclosed by an arbitrary surface, the electric flux through the surface is Gauss?s law can be used to relate the electric field to the enclosed net charge.