22.1

22.2

22.3

22.4

22.5 Charge Attraction Or Repulsion Charging by Transfer

22.6 Charging by Induction Lightning Rod

22.7 Electrical Polarization

22.8 Electrical Polarization

22.9 Electric Fields

22.10 A B Potential Energy B > A Electrical Potential B = A Electric Potential Energy Electric Potential

22.11 Electric Potential Energy vs Potential Capacitor Q = C V High voltage (potential) but Low Potential Energy (due to low charge)

Questions -- MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

) Two charges separated by one meter exert 1-N forces on each other. If the charges are pushed to 1/4 meter separation, the force on each charge will be A)1 N. B)2 N. C)4 N. D)8 N. E) 16 N. 2) Charge carriers in a metal are electrons rather than protons because electrons are A) smaller. B) negative. C) loosely bound. D) all of these. E) none of these.

) The primary purpose of a lightning rod is to A) induce within the structure to which it is attached a charge opposite to that of charged clouds overhead. B) cancel the electric field within the structure to which it is attached. C) attract lightning and guide it to the ground. D) discharge the structure to which it is attached. 4) In an electrically neutral atom the number of protons in the nucleus is equal to the number of A)neutrons in the nucleus. B) electrons that surround the nucleus. C) both of these. D) neither of these.

) Two charged particles held close to each other are released. As they move, the force on each particle increases. Therefore, the particles have A) the same sign. B) opposite signs. C) not enough information given. 6) Two charged particles repel each other with a force F. If the charge of one of the particles is doubled and the distance between them is also doubled, then the force will be A) F/4. B) 2 F. C) F/2. D) F. E) none of these.

) An electron is pushed into an electric field where it acquires a 1-V electrical potential. If two electrons are pushed the same distance into the same electric field, the electrical potential of the two electrons is A)0.25 V. B)0.5 V. C)1 V. D)2 V. E) 4 V. 8) The electrical force on a 2-C charge is 60 N. What is the value of the electric field at the place where the charge is located? A)20 N/C B)30 N/C C)60 N/C D)120 N/C E) 240 N/C

) Normally a balloon charged to several thousand volts has a relatively small amount of A)energy. B)charge. C)both. D) neither. 10) Rub electrons from your hair with a comb and the comb becomes A)negatively charged. B) positively charge.

) If you comb your hair and the comb becomes positively charged, then your hair becomes A)negatively charged. B)positively charged. C) uncharged. 12) An uncharged pith ball is suspended by a nylon fiber. When a negatively charged rubber rod is brought nearby, without touching it, the pith ball A) becomes charged by induction. B) is repelled by the rod. C) becomes polarized. D) all of these. E) none of these.

) To say that an object is electrically polarized is to say A) it is to some degree magnetic. B) its internal electric field is zero. C) it is only partially conducting. D) its charges have been rearranged. E) it is electrically charged. 14) Two charges separated by one meter exert 1-N forces on each other. If the charges are pulled to 3-m separation distance, the force on each charge will be A)0.33 N. B)0.11 N. C)0 N. D)3 N. E) 9 N.

) If you use 10 J of work to push a coulomb of charge into an electric field, its voltage with respect to its starting position is A)less than 10 V. B)more then 10 V. C) 10 V. 16) The electric field inside the dome of a Van de Graaff generator A) depends on its size. B) depends on the amount of charge on it. C) both of these. D) neither of these.

Answers -- MULTIPLE CHOICE. The one alternative that best completes the statement or answers the question.

22.22 Chapter 22 1) Answer: E 2) Answer: C 3) Answer: D 4) Answer: B 5) Answer: B 6) Answer: C 7) Answer: C 8) Answer: B 9) Answer: C 10) Answer: A 11) Answer: A 12) Answer: C 13) Answer: D 14) Answer: B 15) Answer: C 16) Answer: D