Applying The Concepts Ch. 6

1. Electrostatic charge results from a. Transfer or redistribution of electrons. b. Gain or loss of protons. c. Separation of charge from electrons and protons. d. Failure to keep the object clean of dust.

2. unit of electric charge is the a. volt. b. amp. c. coulomb. d. watt.

3. An electric field describes the condition of space around a. A charged particle. b. A magnetic pole. c. A mass. d. All of the above.

4. A material that has elections that are free to move throughout the material is a (an) a. Electrical conductor. b. Electrical insulator. c. Thermal insulator. d. Thermal nonconductor.

5. An example of an electrical insulator is a. Graphite. b. Glass. c. Aluminum. d. Tungsten.

6. The electrical potential difference between two points in a circuit is measured in units of a. volt. b. amp. c. coulomb. d. watt.

7. The rate at which an electric current flow through a circuit is measured in units of a. volt. b. amp. c. coulomb. d. watt.

8. The law that predicts the behavior of electrostatic forces acting through space a. The law of universal gravitation. b. Watt's law. c. Coulomb's law. d. Ohm's law.

9. What type of electric current is produced by fuel cells and solar calls? a. ac b. dc c. 60 Hz d. 120 Hz

10. The electrical resistance of a conductor is measured in units of a. volt. b. amp. c. ohm. d. watt.

11. According to Ohm's law, what must be greater to maintain the same current in a conductor with more resistance? a. Voltage b. Current c. Temperature d. Cross-sectional area

12. A kilowatt-hour is a unit of a. Power. b. Work. c. Current. d. Potential difference.

13. If you multiply volts by amps, the answer will be in units of a. Power. b. Work. c. Current. d. Potential difference.

14. Units of joules per second are a measure called a (an) a. volt. b. amp. c. ohm. d. watt.

15. A lodestone is a natural magnet that attracts a. Iron. b. Cobalt. c. Nickel. d. All of the above.

16. The north pole of a suspended or floating bar magnet currently points directly toward Earth's a. North magnetic pole. b. South magnetic pole. c. North geographic pole. d. South geographic pole.

17. A current-carrying wire always has a. A magnetic field with closed concentric field lines around the length of the wire. b. A magnetic field with field lines parallel to the length of the wire. c. An electric field but no magnetic field around the wire. d. Nothing in the space around the wire.

18. Magnetism is produced by a. An excess of north monopoles. b. An excess of south monopoles. c. Moving charges. d. Separation of positives and negative charges.

19. Earth's magnetic field a. Has undergone many reversals in polarity. b. Has always been as it is now. c. Is created beneath Earth's north geographic pole. d. Is created beneath Earth's south geographic pole.

20. The strength of a magnetic field around a current-carrying wire varies directly with the a. Amperage of the current. b. Voltage of the current. c. Resistance of the wire. d. Temperature of the wire.

21. Reverse the direction of a current in a wire, and the magnetic field around the wire will a. Have an inverse magnitude of strength. b. Have a reverse north pole direction. c. Become a conventional current. d. Remain unchanged.

22. The operation of which of the following depends on the interaction between two magnetic fields? a. Car stereo speakers b. Telephone c. Relay circuit d. All of the above

23. An electric meter measure the a. Actual number of charges moving through a conductor. b. Current in packets of coulombs. c. Strength of a magnetic field. d. Difference in potential between two points in a conductor.

24. When a loop of wire cuts across magnetic field lines or when magnetic field lines move across a loop of wire, a. Electrons are pushed are toward one end of the loop. b. An electrostatic charge is formed. c. The wire becomes a permanent magnet. d. A magnetic domain is created.

25. A step-up transformer steps up the a. Voltage. b. Current. c. Power. d. Energy.

26. Electromagnetic induction occurs when a coil of wire cuts across magnetic field lines. Which one of the following increases the voltage produced? a. Fewer wire loops in the coil b. Increased strength of the magnetic field c. Slower speed of the moving coil of wire d. Decreased strength of the magnetic field

27. Electric power companies step up the voltage of generated power for transmission across the country because higher voltage a. Means more power is transmitted. b. Reduces the current, which increases the resistance. c. Meant less power is transmitted. d. Reduces the current, which lowers the energy lost to resistance.

28. A solar call a. Produces electricity directly. b. Requires chemical reactions c. Has very short lifetime. d. Uses small moving parts.

29. Which of the following is most likely to acquire an electrostatic charge? a. Electrical conductor b. Electrical nonconductor c. Both are equally likely d. None of the above is correct

30. Which of the following units are measures of rates? a. Amp and volt b. Coulomb and joule c. Volt and watt d. Amp and watt

31. You are using which description of a current if you consider a current to be positive charge that flow from the positive to the negative terminal of a battery? a. Electron current b. Conventional current c. Proton current d. Alternation current

32. In an electric current, the electrons are moving a. At a very slow rate. b. At the speed of light. c. Faster than the speed of light. d. At a speed described as supersonic.

33. In which of the following currents is there no electron movement from one end of a conducting wire to the other end? a. Electron current b. Direct current c. Alternation current d. None of the above

34. If you multiply amps by volts, the answer will be in units of a. Resistance. b. Work. c. Currents d. Power.

35. A permanent magnet has magnetic properties because a. The magnetic fields of its electrons are balanced. b. Of an accumulation of monopoles in the ends. c. The magnetic domains are aligned. d. All of the above.

36. A current-carrying wire has a magnetic field around it because a. A moving charge produces a magnetic field of its own. b. The current aligns the magnetic domains in the metal of the wire. c. The metal was magnetic before the current was established, and the current enhanced the magnetic effect. d. None of the above is correct.

37. When an object acquires a negative charge, it actually a. Gains mass. b. Loses mass. c. Has a constant mass. d. The answer is unknown.

38. A positive and a negative charge are initially 2 cm apart. What happens to the force on each as they are moved closer and closer together? The force a. Increases while moving. b. Decreases while moving. c. Remains constant. d. The answer is unknown.

39. To be operational, a complete electric circuit must contain a source of energy, a device that does work, and a. A magnetic field. b. A conductor from the source to the working device and another conductor back to the source c. Connecting wires from the source to the working device. d. A magnetic field and a switch.

40. Which variable is inversely proportional to the resistance? a. Length of conductor b. Cross-sectional area of conductor c. Temperature of conductor d. Conductor material

41. Which of the following is not considered to have strong magnetic properties? a. Iron b. Nickel c. Silver d. Cobalt

42. A piece of iron can be magnetized or unmagnetized. This is explained by the idea that a. Electrons in iron atoms are spinning and have magnetic fields around them. b. Atoms of iron are grouped into tiny magnetic domains that may orient themselves in a particular direction or in a random direction. c. Unmagntized iron atoms can be magnetized by an external magnetic field. d. The north and south poles of iron can be segregated by the application of an external magnetic field.

43. Earth's magnetic field is believed to originate a. By a separation of north and south monopoles due to currents within Earth. b. With electric currents that are somehow generated in Earth's core. c. From a giant iron and cobalt bar magnet inside Earth. d. Form processes that are not understood.

44. The speaker in a stereo system works by the action of a. A permanent magnet creating an electric current. b. An electromagnet pushing and pulling on a permanent magnet. c. Sound waves pushing and pulling on an electromagnet. d. Electrons creating sound waves.

45. Electromagnetic induction takes place because a. An electric current is measured by the rate of movement of charges. b. The potential is determined by how much work is done. c. Electrons have their own magnetic field, which interacts with an externally applied magnetic field. d. Copper wire is magnetic, which induces magnetism.

46. The current in the secondary coil of a transformer is produced by a a. Varying magnetic field. b. Varying electric field. c. Constant magnetic field. d. Constant electric field.

47. An electromagnet uses a. A magnetic field to produce an electric current. b. An electric current to produce an electric current. c. A magnetic current to produce an electric field. d. An electric field to produce a magnetic current.

48. A transformer a. Changes the voltage of a direct current. b. Changes the power of a direct current. c. Changes the voltage of an alternation current. d. Changes the amperage of an alternating current.

49. A parallel circuit has a. Wires that are lined up side by side. b. The same current flowing through one resistance after another. c. Separate pathways for the current to flow through. d. None of the above.

50. In which type of circuit would you expect a reduction of the available voltage as more and more resistances are added to the circuit? a. Series circuit b. Parallel circuit c. Open circuit d. None of the above

51. In which type of circuit would you expect the same voltage with an increased current as more and more resistances are added to the circuit? a. Series circuit b. Parallel circuit c. Open circuit d. None of the above