Gibilisco:Chapter 2 - Electrical Units

20 Questions | Total Attempts: 669

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Gibilisco:Chapter 2 - Electrical Units

This is the MCQs for Gibilisco:CHAPTER 2 - ELECTRICAL UNITS


Questions and Answers
  • 1. 
    A positive electric pole: 
    • A. 

      Has a deficiency of electrons.

    • B. 

      Has fewer electrons than the negative pole.

    • C. 

      Has an excess of electrons.

    • D. 

      Has more electrons than the negative pole

  • 2. 
    An EMF of one volt: 
    • A. 

      Cannot drive much current through a circuit.

    • B. 

      Represents a low resistance.

    • C. 

      Can sometimes produce a large current.

    • D. 

      Drops to zero in a short time.

  • 3. 
    A potentially lethal electric current is on the order of: 
    • A. 

      0.01 mA.

    • B. 

      0.1 mA.

    • C. 

      1 mA.

    • D. 

      0.1 A.

  • 4. 
    A current of 25 A is most likely drawn by: 
    • A. 

      A flashlight bulb.

    • B. 

      A typical household.

    • C. 

      A power plant.

    • D. 

      A clock radio.

  • 5. 
    A piece of wire has a conductance of 20 siemens. Its resistance is: 
    • A. 

      20 Ω.

    • B. 

      0.5 Ω.

    • C. 

      0.05 Ω.

    • D. 

      0.02 Ω.

  • 6. 
    A resistor has a value of 300 ohms. Its conductance is: 
    • A. 

      3.33 millisiemens.

    • B. 

      33.3 millisiemens.

    • C. 

      333 microsiemens.

    • D. 

      0.333 siemens.

  • 7. 
    A mile of wire has a conductance of 0.6 siemens. Then three miles of the same wire has a conductance of: 
    • A. 

      1.8 siemens.

    • B. 

      1.8 Ω.

    • C. 

      0.2 siemens.

    • D. 

      Not enough information has been given to answer this.

  • 8. 
    A 2-kW generator will deliver approximately how much current, reliably, at 117 V? 
    • A. 

      17 mA.

    • B. 

      234 mA.

    • C. 

      17 A.

    • D. 

      234 A.

  • 9. 
    A circuit breaker is rated for 15 A at 117 V. This represents approximately how many kilowatts? 
    • A. 

      1.76

    • B. 

      1760

    • C. 

      7.8

    • D. 

      0.0078

  • 10. 
    You are told that a certain air conditioner is rated at 500 Btu. What is this in kWh? 
    • A. 

      147

    • B. 

      14.7

    • C. 

      1.47

    • D. 

      0.147

  • 11. 
    Of the following energy units, the one most often used to define electrical energy is: 
    • A. 

      The Btu

    • B. 

      The erg

    • C. 

      The foot pound

    • D. 

      The kilowatt hour

  • 12. 
    The frequency of common household ac in the U.S. is: 
    • A. 

      60 Hz

    • B. 

      120 Hz

    • C. 

      50 Hz

    • D. 

      100 Hz

  • 13. 
    Half-wave rectification means that: 
    • A. 

      Half of the ac wave is inverted

    • B. 

      Half of the ac wave is chopped off

    • C. 

      The whole wave is inverted

    • D. 

      The effective value is half the peak value

  • 14. 
    In the output of a half-wave rectifier: 
    • A. 

      Half of the wave is inverted

    • B. 

      The effective value is less than that of the original ac wave

    • C. 

      The effective value is the same as that of the original ac wave

    • D. 

      The effective value is more than that of the original ac wave

  • 15. 
    In the output of a full-wave rectifier: 
    • A. 

      The whole wave is inverted

    • B. 

      The effective value is less than that of the original ac wave

    • C. 

      The effective value is the same as that of the original ac wave

    • D. 

      The effective value is more than that of the original ac wave

  • 16. 
    A low voltage, such as 12 V: 
    • A. 

      Is never dangerous

    • B. 

      Is always dangerous

    • C. 

      Is dangerous if it is ac, but not if it is dc

    • D. 

      Can be dangerous under certain conditions

  • 17. 
    Which of these can represent magnetomotive force? 
    • A. 

      The volt-turn

    • B. 

      The ampere-turn

    • C. 

      The gauss

    • D. 

      The gauss-turn

  • 18. 
    Which of the following units can represent magnetic flux density? 
    • A. 

      The volt-turn

    • B. 

      The ampere-turn

    • C. 

      The gauss

    • D. 

      The gauss-turn

  • 19. 
    A ferromagnetic material: 
    • A. 

      Concentrates magnetic flux lines within itself

    • B. 

      Increases the total magnetomotive force around a current-carrying wire

    • C. 

      Causes an increase in the current in a wire

    • D. 

      Increases the number of ampere-turns in a wire

  • 20. 
    A coil has 500 turns and carries 75 mA of current. The magnetomotive force will be: 
    • A. 

      37,500 At

    • B. 

      375 At

    • C. 

      37.5 At

    • D. 

      3.75 At

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