Enter your Name:   Enter your E-mail Address:  Be sure to write all your answers with the proper number of significant figures and to list the units that go with your answers! 01. A physicist uses a positively charged rod to give a metal sphere a negative charge. Did the physicist charge by conduction or induction? 02. An ion has more protons than electrons What is the sign of its electrical charge? 03. Two charged objects (one positive and one negative) are held apart with a long bar: If the charge of these two objects does not change, even after a long time, is the bar made of an insulator or a conductor? 04. When we use Coulomb's Law to calculate the force that exists between two charges which are free to move, we say that we are calculating the instantaneous electrostatic force. Why must we say "instantaneous"? 05. Two charged objects are isolated in space. The charge on the positive object is twice the charge on the negative object. If the positive object exertds a 5.0 N force on the negative object, how much force does thenegative object exert on the positive one? 06. Two charged objects are held in place and the electrostatic force between them is measured. If, suddenly, half of the charge is taken out of one of the objects, what happens to the magnitude of the force? 07. Two charged objects are held in place and the electrostatic force between them is measured. If, suddenly, the distance between the objects is halved, what happens to the magnitude of the force? 08. A +2.1 C charge is placed 45 cm from a -9.3 C charge. What is the force between them? Is it attractive or repulsive? 09. Two charged objects that are 1.2 m apart experience a repulsive instantaneous electrostatic force of 4.3 x 105 Newtons. If one of the objects is charged at +3.1 mC, what is the charge (include the sign) of the other object? 10. Three charges are arranged as follows: What is the instantaneous electrostaic force on the +6.4 mC charge: 11. Three charges are arranged as follows: What is the instantaneous electrostatic force on the +7.6 mC particle? 12. Consider the following electrostatic field: a. Is particle B positive or negatively charged? b. If the magnitude of particle A's charge is 1.0 C, what is the magnitude of particle B's charge? c. Where shoud a freely-moving charge be placed so that it experiences the least acceleration? 13. Four protons are placed at the vertices of a square. Draw the electrical field that results: 14. What is the speed of an electron (q = -1.6 x 10-19 C, m = 9.1 x 10-31 kg) in a Li2+ ion if it orbits the nucleus at a distance of 5.9 x 10-12 m? This ion is made up of three protons (q = 1.6 x 10-19 C each), 2 neutrons, and 1 electron.