1.If you charge a pocket comb by rubbing it with a silk scarf, how can you determine if the comb is positively or negatively charged? 6.Contrast the net charge on a conductor to the "free charges" in the conductor. 7.A charged rod placed near an unchanged metal object can attract(or repel) electrictrons. There are a great many electrons in the metal, yet only some of them move. Why not all of them? 12. What experimental observations mentioned in the text rule out the possibility that the numerator in Coulomb's law contains the sum (Q1 and Q2)rather than the product Q1Q2? 20.Show, using the three rules for field lines, that the electric field lines starting or ending on a single point charge must be symmetrically spaced around the charge. THREE RULES: A.The field lines indicate the direction of the electric field;the field points in the direction tangent to the field line at any point; B.The lines are drawn so that the magnitude of the electric field, E, is proportional to the number of lines crossing unit area perpendicular to the lines. The closer the lines, the stronger the field; C.Electric field lines start on positive charges and end on negative charges; and the number starting or ending is proportional to the magnitude of the charge. 23.Consider a small positive test charge located on an electric field line at some point, such as point P. Is the direction of the velocity and/or acceleration of the test charge alone this line? Discuss. 24.We wish to determine the electric field at a point near a positively charged metal sphere(a good conductor).We do so by bringing a small test charge, q0, to this point and measure the force F0 on it. Will F0/q0 be greater than, less than, or equal to, the electric field E as it was at that point before the test charge was present?