Chapter 23: Electric Current

67 Questions

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Electric Current Quizzes & Trivia

Questions and Answers
  • 1. 
    Electrons are made to flow in a wire when there is
    • A. 

      An imbalance of charges in the wire.

    • B. 

      More potential energy at one end of the wire than the other.

    • C. 

      A potential difference across its ends.

  • 2. 
    An ampere is a unit of electrical
    • A. 

      Pressure.

    • B. 

      Current.

    • C. 

      Resistance.

    • D. 

      All of these

    • E. 

      None of these

  • 3. 
    A wire that carries an electric current
    • A. 

      Is electrically charged.

    • B. 

      May be electrically charged.

    • C. 

      Is never electrically charged.

  • 4. 
    A coulomb of charge that passes through a 6-volt battery is given
    • A. 

      6 joules.

    • B. 

      6 amperes.

    • C. 

      6 ohms.

    • D. 

      6 watts.

    • E. 

      6 newtons.

  • 5. 
    Which statement is correct?
    • A. 

      Charge flows in a closed circuit.

    • B. 

      Voltage flows through an open or a closed circuit.

    • C. 

      Resistance flows through an open circuit.

    • D. 

      Current is the primary cause of voltage.

  • 6. 
    Electrons move in an electrical circuit
    • A. 

      By being bumped by other electrons.

    • B. 

      By colliding with molecules.

    • C. 

      By interacting with an established electric field.

    • D. 

      Because the wires are so thin.

    • E. 

      None of these

  • 7. 
    Stretch a copper wire so that it is thinner and the resistance between its ends
    • A. 

      Decreases.

    • B. 

      Remains unchanged.

    • C. 

      Increases.

  • 8. 
    Heat a copper wire and its electric resistance
    • A. 

      Decreases.

    • B. 

      Remains unchanged.

    • C. 

      Increases.

  • 9. 
    A wire carrying a current is normally charged
    • A. 

      Negatively.

    • B. 

      Positively.

    • C. 

      Not at all.

  • 10. 
    In an ac circuit, the electric field
    • A. 

      Increases via the inverse-square law.

    • B. 

      Changes magnitude and direction with time.

    • C. 

      Is the same everywhere.

    • D. 

      Is non-existent.

    • E. 

      None of these

  • 11. 
    The current through a 10-ohm resistor connected to a 120-V power supply is
    • A. 

      1 A.

    • B. 

      10 A.

    • C. 

      12 A.

    • D. 

      120 A.

    • E. 

      None of these

  • 12. 
    A 10-ohm resistor has a 5-A current in it. What is the voltage across the resistor?
    • A. 

      5 V

    • B. 

      10 V

    • C. 

      15 V

    • D. 

      20 V

    • E. 

      More than 20 V

  • 13. 
    When a 10-V battery is connected to a resistor, the current in the resistor is 2 A. What is the resistor's value?
    • A. 

      2 ohms

    • B. 

      5 ohms

    • C. 

      10 ohms

    • D. 

      20 ohms

    • E. 

      More than 20 ohms

  • 14. 
    The primary source of electrons in an ordinary electrical circuit is
    • A. 

      A dry cell, wet cell or battery.

    • B. 

      The back emf of motors.

    • C. 

      The power station generator.

    • D. 

      The electrical circuit itself.

    • E. 

      None of these

  • 15. 
    The source of electrons lighting an incandescent ac light bulb is
    • A. 

      The power company.

    • B. 

      Electrical outlet.

    • C. 

      Atoms in the light bulb filament.

    • D. 

      The wire leading to the lamp.

    • E. 

      The source voltage.

  • 16. 
    A woman experiences an electrical shock. The electrons making the shock come from the
    • A. 

      Woman's body.

    • B. 

      Ground.

    • C. 

      Power plant.

    • D. 

      Hairdryer.

    • E. 

      Electric field in the air.

  • 17. 
    In a common dc circuit, electrons move at speeds of
    • A. 

      A fraction of a centimeter per second.

    • B. 

      Many centimeters per second.

    • C. 

      The speed of a sound wave.

    • D. 

      The speed of light.

    • E. 

      None of these

  • 18. 
    When a light switch is turned on in a dc circuit, the average speed of electrons in the lamp is
    • A. 

      The speed of sound waves in metal.

    • B. 

      The speed of light.

    • C. 

      1000 cm/s.

    • D. 

      Less than 1 cm/s.

    • E. 

      Dependent on how quickly each electron bumps into the next electron.

  • 19. 
    Alternating current is normally produced by a
    • A. 

      Battery.

    • B. 

      Generator.

    • C. 

      Both of these

    • D. 

      Neither of these

  • 20. 
    The electric power of a lamp that carries 2 A at 120 V is
    • A. 

      1/6 watts.

    • B. 

      2 watts.

    • C. 

      60 watts.

    • D. 

      20 watts.

    • E. 

      240 watts.

  • 21. 
    When two lamps are connected in parallel to a battery, the electrical resistance that the battery senses is
    • A. 

      More than the resistance of either lamp.

    • B. 

      Less than the resistance of either lamp.

    • C. 

      None of these

  • 22. 
    When two lamps are connected in series to a battery, the electrical resistance that the battery senses is
    • A. 

      More than the resistance of either lamp.

    • B. 

      Less than the resistance of either lamp.

    • C. 

      None of these

  • 23. 
    On some early automobiles both headlights went out when one bulb burned out. The headlights must have been connected in
    • A. 

      Parallel.

    • B. 

      Perpendicular.

    • C. 

      Series.

    • D. 

      Haste.

  • 24. 
    Modern automobile headlights are connected in
    • A. 

      Parallel.

    • B. 

      Perpendicular.

    • C. 

      Series.

    • D. 

      None of these

  • 25. 
    There are electrons in the filament of the ac lamp in your bedroom. When you turn on the lamp and it glows, the glowing comes from
    • A. 

      Different electrons; the ones that flow in the circuit to your lamp.

    • B. 

      The same electrons.

    • C. 

      The positive charges that flow in the filament.

  • 26. 
    A 100-Watt lamp glows brighter than a 25-Watt lamp. The electrical resistance of the 100-Watt lamp must be
    • A. 

      Less.

    • B. 

      Greater.

    • C. 

      The same.

  • 27. 
    In an electric circuit, the safety fuse is connected to the circuit in
    • A. 

      Series.

    • B. 

      Parallel.

    • C. 

      Either series or parallel.

  • 28. 
    When two 1-ohm resistors are connected in series, their combined resistance is
    • A. 

      1 ohm, and when connected in parallel, 2 ohms.

    • B. 

      2 ohms, and when in parallel, 1 ohm.

    • C. 

      1/2 ohm, and when in parallel, 2 ohms.

    • D. 

      2 ohms, and when in parallel, 1/2 ohm.

    • E. 

      None of these

  • 29. 
    A circuit breaker often serves the same purpose as a
    • A. 

      Battery

    • B. 

      Fuse.

    • C. 

      Capacitor.

    • D. 

      All of the above choices are correct.

    • E. 

      None of the above choices are correct.

  • 30. 
    A capacitor is useful in
    • A. 

      Boosting the energy output of a circuit.

    • B. 

      Increasing the current in a resistor.

    • C. 

      Smoothing pulsed current.

    • D. 

      Switching dc to ac in a circuit.

    • E. 

      Increasing or decreasing voltage.

  • 31. 
    An electrical diode is useful for
    • A. 

      Storing electrical energy.

    • B. 

      Boosting voltage.

    • C. 

      Limiting current.

    • D. 

      Voltage modification.

    • E. 

      Changing ac to dc.

  • 32. 
    In a 110-volt circuit containing a lamp in series with the voltage source
    • A. 

      110 coulombs of charge flow through the lamp every second.

    • B. 

      110 joules of energy are converted to heat and light in the circuit every second.

    • C. 

      110 joules of energy are given up by each coulomb of charge making up the current in the circuit.

    • D. 

      110 joules of energy are shared among all the coulombs in the circuit at any instant.

    • E. 

      None of the above

  • 33. 
    In a simple circuit containing a bulb, energy is given to the moving charges by
    • A. 

      The bulb.

    • B. 

      The wires.

    • C. 

      A generator.

    • D. 

      None of these

  • 34. 
    A capacitor is used to store
    • A. 

      Both charge and energy.

    • B. 

      Energy.

    • C. 

      Charge.

    • D. 

      Neither charge nor energy.

  • 35. 
    The number of electrons delivered daily to an average American home by an average power utility in the mid 1980s was
    • A. 

      Zero.

    • B. 

      110.

    • C. 

      220.

    • D. 

      Billions of billions.

    • E. 

      None of these

  • 36. 
    Two lamps, one with a thick filament and one with a thin filament, are connected in series. The current is
    • A. 

      Greater in the lamp with the thick filament.

    • B. 

      Greater in the lamp with the thin filament.

    • C. 

      The same in each lamp.

  • 37. 
    Two lamps, one with a thick filament and one with a thin filament, are connected in parallel to a battery. The voltage is
    • A. 

      Greatest across the lamp with the thick filament.

    • B. 

      Greatest across the lamp with the thin filament.

    • C. 

      The same in both lamps.

  • 38. 
    Two lamps, one with a thick filament and one with a thin filament of the same material, are connected in parallel to a battery. The current is
    • A. 

      Larger in the lamp with the thick filament.

    • B. 

      Larger in the lamp with the thin filament.

    • C. 

      The same in both lamps.

  • 39. 
    Two lamps, one with a thick filament and one with a thin filament of the same material, are connected in series to a battery. The voltage is
    • A. 

      Greater across the lamp with the thick filament.

    • B. 

      Greater across the lamp with the thin filament.

    • C. 

      The same for both lamps.

  • 40. 
    As more lamps are put into a series circuit, the overall current in the power source
    • A. 

      Increases.

    • B. 

      Decreases.

    • C. 

      Stays the same.

  • 41. 
    As more lamps are put into a parallel circuit, the overall current in the power source
    • A. 

      Increases.

    • B. 

      Decreases.

    • C. 

      Stays the same.

  • 42. 
    A circuit is powered with a battery. Charge flows
    • A. 

      Out of the battery and into the circuit.

    • B. 

      From the negative battery terminal to the positive terminal.

    • C. 

      Only after a couple seconds pass.

    • D. 

      Through both the battery and the rest of the circuit.

    • E. 

      None of these

  • 43. 
    When we say an appliance "uses up electricity," we really are saying that
    • A. 

      Current disappears.

    • B. 

      Electric charges are dissipated.

    • C. 

      The main power supply voltage is lowered.

    • D. 

      Electrons are removed from the circuit and placed elsewhere.

    • E. 

      Electron kinetic energy is changed into heat.

  • 44. 
    Compared to the resistance of two resistors connected in series, the same two resistors connected in parallel have
    • A. 

      More resistance.

    • B. 

      Less resistance.

    • C. 

      The same resistance.

  • 45. 
    If you plug an electric toaster rated at 110 V into a 220-V outlet, the current in the toaster will be about
    • A. 

      Half what it should be.

    • B. 

      The same as if it were plugged into 110 V.

    • C. 

      More than twice what it should be.

    • D. 

      Twice what it should be.

  • 46. 
    When a 60-watt light bulb is connected to a 120-volt source the current in the light bulb is
    • A. 

      0.25 A.

    • B. 

      0.5 A.

    • C. 

      2 A.

    • D. 

      4 A.

    • E. 

      More than 4 A.

  • 47. 
    If 0.8 A of current flow through a light bulb connected to a 120 V outlet, the power consumed is
    • A. 

      12 W.

    • B. 

      15 W.

    • C. 

      60 W.

    • D. 

      96 W.

    • E. 

      120 W.

  • 48. 
    The headlights, radio, and defroster fan in an automobile are connected in
    • A. 

      Series with a switch for each.

    • B. 

      Parallel with a switch for each.

    • C. 

      Series without separate switches.

    • D. 

      Parallel without separate switches.

  • 49. 
    A 4-ohm resistor is connected in parallel with a 6-ohm resistor. This combination produces an equivalent resistance of
    • A. 

      2.4 ohms.

    • B. 

      4 ohms.

    • C. 

      5 ohms.

    • D. 

      5.5 ohms.

    • E. 

      10 ohms.

  • 50. 
    The power dissipated in a 4-ohm resistor carrying 3 A is
    • A. 

      7 W.

    • B. 

      18 W.

    • C. 

      36 W.

    • D. 

      48 W.

    • E. 

      Not enough information to say

  • 51. 
    Which is more dangerous, touching a faulty 110-volt light fixture, or a Van de Graaff generator charged to 100,000 volts?
    • A. 

      Touching the light fixture

    • B. 

      Touching the generator

    • C. 

      Touching both are about equally dangerous.

  • 52. 
    A 60-W light bulb and a 100-W light bulb are each rated at 120 V. Which light bulb has a larger resistance?
    • A. 

      The 60-W bulb

    • B. 

      The 100-W bulb

    • C. 

      Both have the same resistance.

  • 53. 
    A 60-W light bulb and a 100-W light bulb are connected in series to a 120 V outlet. Which light bulb has more current in it?
    • A. 

      The 60-W bulb

    • B. 

      The 100-W bulb

    • C. 

      Both have the same current.

  • 54. 
    Compared to the filament thickness of a 60-W light bulb, the filament of a 100-W light bulb will be
    • A. 

      Thinner.

    • B. 

      Thicker.

    • C. 

      The same.

  • 55. 
    Compared to a single lamp connected to a battery, two identical lamps connected in series to the same battery will carry
    • A. 

      More current.

    • B. 

      Less current.

    • C. 

      The same current.

  • 56. 
    Compared to a single lamp connected to a battery, two lamps connected in parallel to the same battery will carry
    • A. 

      More current.

    • B. 

      Less current.

    • C. 

      The same current.

  • 57. 
    An electric heater is rated at 300 W when used in a 110-V circuit. The safety fuse in the circuit can handle 15 A of current. How many heaters can be safely operated in the circuit?
    • A. 

      2

    • B. 

      3

    • C. 

      4

    • D. 

      5

    • E. 

      More than 5

  • 58. 
    A heater uses 20 A when used in a 110-V line. If electric power costs 10 cents per kilowatt hour, the cost of running the heater for 10 hours is
    • A. 

      $0.22.

    • B. 

      $0.55.

    • C. 

      $2.20.

    • D. 

      $5.50.

    • E. 

      None of these

  • 59. 
    The current through two identical light bulbs connected in series is 0.25 A. The voltage across both bulbs is 110 V. The resistance of a single light bulb is
    • A. 

      22 ohms.

    • B. 

      44 ohms.

    • C. 

      220 ohms.

    • D. 

      440 ohms.

    • E. 

      None of these

  • 60. 
    A power line with a resistance of 2 ohms has a current of 80 A in it. The power dissipated in the line is
    • A. 

      40 W.

    • B. 

      160 W.

    • C. 

      320 W.

    • D. 

      12,800 W.

    • E. 

      None of these

  • 61. 
    What is the resistance of a 120-W incandescent lamp connected to a 120-V power supply?
    • A. 

      1 ohm

    • B. 

      60 ohms

    • C. 

      100 ohms

    • D. 

      144 ohms

    • E. 

      None of these

  • 62. 
    Compared to the amount of electric current in the filament of a lamp, the amount of current in the connecting wire is
    • A. 

      Definitely less.

    • B. 

      Often less.

    • C. 

      Actually more.

    • D. 

      The same.

    • E. 

      Incredibly, all of these

  • 63. 
    Connect a pair of lamps in series and you draw current from the connected battery. Connect the same lamps in parallel and you draw
    • A. 

      The same current.

    • B. 

      More current.

    • C. 

      Less current.

    • D. 

      Sometimes more, sometimes less.

  • 64. 
    Three resistors, 1-ohm, 2-ohm, and 3- ohm are connected in parallel. If they were connected in series instead their equivalent resistance would be
    • A. 

      7 times as great.

    • B. 

      9 times as great.

    • C. 

      11 times as great.

    • D. 

      13 times as great.

    • E. 

      None of the above choices are correct.

  • 65. 
    The ratio of the potential difference across a metallic conductor to the current in the conductor is known as
    • A. 

      Potential drop.

    • B. 

      Conductivity.

    • C. 

      Resistance.

    • D. 

      Electromagnetic force.

    • E. 

      None of the above choices are correct.

  • 66. 
    What condition must exist between two points in a conductor in order to maintain a flow of charge?
    • A. 

      A steady magnetic field

    • B. 

      A high resistance

    • C. 

      A switch connected in series

    • D. 

      All of the above choices are correct.

    • E. 

      None of the above choices are correct.

  • 67. 
    A sphere has a negative charge of 6.4 × 10^(-7) coulomb. The approximate number of electrons that must be removed to make the sphere neutral is
    • A. 

      1.6 × 10^(-8).

    • B. 

      9.8 × 10^3.

    • C. 

      6.4 × 10^26.

    • D. 

      4.0 × 10^12.