Gibilisco: Chapter 8 - Magnetism

20 Questions | Total Attempts: 469

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Gibilisco: Chapter 8 - Magnetism

This is the MCQs for Gibilisco: CHAPTER 8 - Magnetism


Questions and Answers
  • 1. 
    The geomagnetic field:
    • A. 

      Makes the earth like a huge horseshoe magnet

    • B. 

      Runs exactly through the geographic poles

    • C. 

      Is what makes a compass work

    • D. 

      Is what makes an electromagnet work

  • 2. 
    Geomagnetic lines of flux:
    • A. 

      Are horizontal at the geomagnetic equator

    • B. 

      Are vertical at the geomagnetic equator

    • C. 

      Are always slanted, no matter where you go

    • D. 

      Are exactly symmetrical around the earth, even far out into space

  • 3. 
    A material that can be permanently magnetized is generally said to be:
    • A. 

      Magnetic

    • B. 

      Electromagnetic

    • C. 

      Permanently magnetic

    • D. 

      Ferromagnetic

  • 4. 
    The force between a magnet and a piece of ferromagnetic metal that has not been magnetized:
    • A. 

      Can be either repulsive or attractive

    • B. 

      Is never repulsive

    • C. 

      Gets smaller as the magnet gets closer to the metal

    • D. 

      Depends on the geomagnetic field

  • 5. 
    Magnetic flux can always be attributed to:
    • A. 

      Ferromagnetic materials

    • B. 

      Aligned atoms

    • C. 

      Motion of charged particles

    • D. 

      The geomagnetic field

  • 6. 
    Lines of magnetic flux are said to originate:
    • A. 

      In atoms of ferromagnetic materials

    • B. 

      At a north magnetic pole

    • C. 

      Where the lines converge to a point

    • D. 

      In charge carriers

  • 7. 
    The magnetic flux around a straight, current-carrying wire:
    • A. 

      Gets stronger with increasing distance from the wire

    • B. 

      Is strongest near the wire

    • C. 

      Does not vary in strength with distance from the wire

    • D. 

      Consists of straight lines parallel to the wire

  • 8. 
    The gauss is a unit of:
    • A. 

      Overall magnetic field strength

    • B. 

      Ampere-turns

    • C. 

      Magnetic flux density

    • D. 

      Magnetic power

  • 9. 
    A unit of overall magnetic field quantity is the:
    • A. 

      Maxwell

    • B. 

      Gauss

    • C. 

      Tesla

    • D. 

      Ampere-turn

  • 10. 
    If a wire coil has 10 turns and carries 500 mA of current, what is the magnetomotive force in ampere-turns?
    • A. 

      5000

    • B. 

      50

    • C. 

      5.0

    • D. 

      0.02

  • 11. 
    If a wire coil has 100 turns and carries 1.30 A of current, what is the magnetomotive force in gilberts?
    • A. 

      130

    • B. 

      76.9

    • C. 

      164

    • D. 

      61.0

  • 12. 
    Which of the following is not generally possible in a geomagnetic storm?
    • A. 

      Charged particles streaming out from the sun

    • B. 

      Fluctuations in the earth’s magnetic field

    • C. 

      Disruption of electrical power transmission

    • D. 

      Disruption of microwave radio links

  • 13. 
    An ac electromagnet:
    • A. 

      Will attract only other magnetized objects

    • B. 

      Will attract pure, unmagnetized iron

    • C. 

      Will repel other magnetized objects

    • D. 

      Will either attract or repel permanent magnets, depending on the polarity

  • 14. 
    An advantage of an electromagnet over a permanent magnet is that:
    • A. 

      An electromagnet can be switched on and off

    • B. 

      An electromagnet does not have specific polarity

    • C. 

      An electromagnet requires no power source

    • D. 

      Permanent magnets must always be cylindrical

  • 15. 
    A substance with high retentivity is best suited for making:
    • A. 

      An ac electromagnet

    • B. 

      A dc electromagnet

    • C. 

      An electrostatic shield

    • D. 

      A permanent magnet

  • 16. 
    A relay is connected into a circuit so that a device gets a signal only when the relay coil carries current. The relay is probably:
    • A. 

      An ac relay

    • B. 

      A dc relay

    • C. 

      Normally closed

    • D. 

      Normally open

  • 17. 
    A device that reverses magnetic field polarity to keep a dc motor rotating is:
    • A. 

      A solenoid

    • B. 

      An armature coil

    • C. 

      A commutator

    • D. 

      A field coil

  • 18. 
    A high tape-recorder motor speed is generally used for:
    • A. 

      Voices

    • B. 

      Video

    • C. 

      Digital data

    • D. 

      All of the above

  • 19. 
    An advantage of a magnetic disk, as compared with magnetic tape, for data storage and retrieval is that:
    • A. 

      A disk lasts longer

    • B. 

      Data can be stored and retrieved more quickly with disks than with tapes

    • C. 

      Disks look better

    • D. 

      Disks are less susceptible to magnetic fields

  • 20. 
    A bubble memory is best suited for:
    • A. 

      A large computer

    • B. 

      A home video entertainment system

    • C. 

      A portable cassette player

    • D. 

      A magnetic disk

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