1. Common static electricity involves charges ranging from nanocoulombs to microcoulombs. (a) How many electrons are needed to form a charge of2.00 TIC (b) How many electrons must be removed from a neutral object to leave a net charge of 0.500 pC? "1'1 7. A50.o g ball of copper has a net charge of 2.00 uC. What fraction of the copper's electrons has been removed? (Each copper atom has 29 protons, and copper has an atomic mass of 63.5.)13. Two point charges are brought closer together, increasing the force between them by a factor of 25. By what factor was their separation decreased? 32. (a) Find the magnitude and direction of an electric field that exerts a 4.80 x 10-17 N westward force on an electron. (b) What magnitude and direction force does this field exert on a proton?33. (a) Sketch the electric field lines near a point charge +9. (b) Do the same for a point charge -3.00q.37. Sketch the electric field lines in the vicinity of the conductor in Figure 18.48 given the field was originally uniform and parallel to the object's long axis. Is the resulting field small near the long side of the object? Figure 18.486. What can you say about two charges q1 and 92, if the electric field one-fourth of the way from 91 to 92 is zero