Electricity M/C

B

18) To say that an object is electrically polarized is to say A) it is electrically charged. B) its charges have been rearranged. C) its internal electric field is zero. D) it is only partially conducting. E) it is to some degree magnetic.

C

19) A balloon will stick to a wooden wall if the balloon is charged A) negatively. B) positively. C) either way. D) neither way.

D

2) The fundamental force underlying all chemical reactions is A) gravitational. B) nuclear. C) centripetal. D) electrical. E) none of these.

C

4) A positive ion has more A) electrons than neutrons. B) electrons than protons. C) protons than electrons. D) protons than neutrons. E) neutrons than protons.

A

10) The electrical force between charges is strongest when the charges are A) close together. B) far apart. C) the electric force is constant everywhere.

C

11) The electrical force between charges depends on the A) magnitude of electric charges. B) separation distance between electric charges. C) both of these. D) none of these.

C

1) Which force binds atoms together to form molecules? A) gravitational B) nuclear C) electrical D) centripetal E) none of these

C

12) A transistor is an example of A) a resistor. B) a superconductor. C) a semiconductor. D) a dry cell. E) electrostatic shielding

C

13) Superconductors are noted for their A) high electric resistance. B) low electric resistance. C) absence of electric resistance.

A

14) Rub electrons from your hair with a comb and the comb becomes A) negatively charged. B) positively charge.

A

15) An electron and a proton A) attract each other. B) repel each other.

B

16) Two protons attract each other gravitationally and repel each other electrically. By far the greater is A) the gravitational attraction. B) the electrical repulsion. C) neither - they are the same.

B

17) The primary purpose of a lightning rod is to A) attract lightning and guide it to the ground. B) discharge the structure to which it is attached. C) cancel the electric field within the structure to which it is attached. D) induce within the structure to which it is attached a charge opposite to that of charged clouds overhead.

D

20) When a car is struck by lightning, the resulting electric field inside the car is A) normally huge, but for a brief time. B) normally huge for a time longer than the lightning stroke itself. C) small enough to be safe for an occupant inside. D) zero.

C

21) Electric potential, measured in volts, is the ratio of electric energy to amount of electric A) current. B) resistance. C) charge. D) voltage. E) none of these.

D

22) The electric field inside the dome of a Van de Graaff generator A) depends on the amount of charge on it. B) depends on its size. C) both of these. D) neither of these.

B

23) 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) becomes polarized. C) is repelled by the rod. D) all of these. E) none of these.

E

24) The net charge on a charged capacitor A) depends on the area of the capacitor plates. B) depends on the distance between the capacitor plates. C) depends on the medium between the capacitor plates. D) all of these. E) none of these - the net charge is zero.

A

25) Charges on the plates of a charged capacitor reside on the surfaces A) between the capacitor plates. B) exterior to the capacitor.

A

26) When the distance between two charges is halved, the electrical force between the charges A) quadruples. B) doubles. C) halves. D) is reduced by 1/4. E) none of these.

C

27) Particle A and Particle B interact with each other. Particle A has twice the charge of particle B. Compared to the force on Particle A, the force on Particle B is A) four times as much. B) two times as much. C) the same. D) half as much. E) none of these.

B

28) If you comb your hair and the comb becomes positively charged, then your hair becomes A) positively charged. B) negatively charged. C) uncharged.

D

29) To say that electric charge is conserved means that no case has ever been found where A) the total charge on an object has changed. B) the net amount of negative charge on an object is unbalanced by a positive charge on another object. C) the total amount of charge on an object has increased. D) net charge has been created or destroyed. E) none of these.

A

3) In an electrically neutral atom the number of protons in the nucleus is equal to the number of A) electrons that surround the nucleus. B) neutrons in the nucleus. C) both of these. D) neither of these.

B

30) A difference between electric forces and gravitational forces is that electrical forces include A) separation distance. B) repulsive interactions. C) the inverse square law. D) infinite range. E) none of these.

E

31) A conductor differs from an insulator in that a conductor A) has more electrons than protons. B) has more protons than electrons. C) has more energy than an insulator. D) has faster moving molecules. E) none of these.

A

32) A negatively charged rod is brought near a metal can that rests on a wood table. You touch the opposite side of the can momentarily with your finger. The can is then A) positively charged. B) negatively charged. C) uncharged. D) charged the same as it was.

C

33) Every proton in the universe is surrounded by its own A) electric field. B) gravitational field. C) both of these. D) none of these.

D

34) The direction of an electric field is the direction of the force that it would exert on A) a neutron. B) an electron. C) an atom. D) a proton. E) a molecule.

E

35) The electric field around an isolated electron has a certain strength 1 cm from the electron. The electric field strength 2 cm from the electron is A) half as much. B) the same. C) twice as much. D) four times as much. E) none of these.

B

36) 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) 10 V. C) more then 10 V.

B

37) If you use 10 J of work to push a charge into an electric field and then release the charge, as it flies past its starting position, its kinetic energy is A) less than 10 J. B) 10 J. C) more than 10 J.

A

38) An electroscope is charged positively as shown by foil leaves that stand apart. As a negative charge is brought close to the electroscope, the leaves A) fall closer together. B) spread apart further. C) do not move.

C

39) Charge carriers in a metal are electrons rather than protons because electrons are A) negative. B) smaller. C) loosely bound. D) all of these. E) none of these.

A

40) To be safe in the unlikely case of a lightning strike, it is best to be inside a building framed with A) steel. B) wood. C) both the same.

B

41) A charged balloon neatly illustrates that something can have a great amount of A) potential energy and a low voltage. B) voltage and a small potential energy. C) both voltage and potential energy. D) none of these.

C

42) Normally a balloon charged to several thousand volts has a relatively small amount of A) charge. B) energy. C) both. D) neither.

A

43) You can touch a 100,000-volt Van de Graaff generator with little harm because although the voltage is high, the relatively small amount of charge means there is a relatively small amount of A) energy. B) electric field. C) polarization. D) conduction.

E

44) 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.

B

45) 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.

C

46) Two charges separated by one meter exert 1-N forces on each other. If the magnitude of each charge is doubled, the force on each charge is A) 1 N. B) 2 N. C) 4 N. D) 8 N. E) none of these.

B

47) 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

C

48) 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. B) 2 F. C) F/2. D) F/4. E) none of these.

A

49) Two charged particles attract each other with a force F. If the charges of both particles are doubled, and the distance between them also doubled, then the force of attraction will be A) F. B) 2 F. C) F/2. D) F/4. E) none of these.

E

50) When a single charge q is placed on one corner of a square, the electric field at the center of the square is F/q. If three other equal charges are placed on the other corners, the electric field at the center of the square due to these four equal charges is A) F/q. B) 4F/q. C) F/(2q). D) F/(4q). E) none of these.

A

51) When a single charge q is placed at one corner of a square, the electric field at the center of the square is F/q. If two other equal charges are placed at the adjacent corners of the square, the electric field at the center of the square due to these three equal charges is A) F/q. B) 4F/q. C) F/(2q). D) F/(4q). E) none of these.

C

52) 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.

B

53) The electric field inside an uncharged metal ball is zero. If the ball is negatively charged, the electric field inside the ball is then A) less than zero. B) zero. C) greater than zero.

B

54) 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.

C

55) Two charged particles held close to each other are released. As the particles move, the velocity of each increases. Therefore, their charges have A) the same sign. B) opposite signs. C) not enough information given.

A

56) A positive charge and a negative charge held near each other are released. As they move, the force on each particle A) increases. B) decreases. C) stays the same.

A

57) Two charged particles held near each other are released. As they move, the acceleration of each decreases. Therefore, the particles have A) the same sign. B) opposite signs. C) not enough information given.

A

58) A proton and an electron are placed in an electric field. Which undergoes the greater acceleration? A) electron B) proton C) both accelerate equally D) neither accelerates

B

6) To say that electric charge is quantized is to say that the charge on an object A) may occur in an infinite variety of quantities. B) is a whole-number multiple of the charge of one electron. C) will interact with neighboring electric charges. D) can be neither created nor destroyed.

A

5) Strip electrons from an atom and the atom becomes a A) positive ion. B) negative ion. C) different element.

D

7) To say that electric charge is conserved is to say that electric charge A) may occur in an infinite variety of quantities. B) is a whole number multiple of the charge of one electron. C) will interact with neighboring electric charges. D) can be neither created nor destroyed.

B

8) The unit of electric charge, the coulomb, is the charge on A) one electron. B) a specific large number of electrons.

B

9) A main difference between gravitational and electric forces is that electrical forces A) attract. B) repel or attract. C) obey the inverse-square law. D) act over shorter distances. E) are weaker.