Week 3: The Electric Field Due to an Electric Dipole, The Electric Field Due to a Line of Charge, Check points, Questions
Today we review the concept of electric charge, and describe both how charges create electric fields and how those electric fields can in turn exert forces on other charges. Again, the electric field is completely analogous to the gravitational field, where mass is replaced by electric charge, with the small exceptions that (1) charges can be either positive or negative while mass is always positive, and (2) while masses always attract, charges of the same sign repel (opposites attract). We will also introduce the concepts of understanding and calculating the electric field generated by a continuous distribution of charge.