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  • Question
  • What is the flux density of a magnetic field whose flux is 3000 µWb and cross-sectional area is 0.25 m2?


  • Options
  • A. 12,000 µT
  • B. 83,330 T
  • C. 0 T
  • D. More information is needed in order to find flux density.

  • Correct Answer
  • 12,000 µT 


  • Magnetism and Electromagnetism problems


    Search Results


    • 1. What is the reluctance of a material that has a length of 0.045 m, a cross-sectional area of 0.015 m2, and a permeability of 2500 µWb/At·m?

    • Options
    • A. 833.33 µAt/Wb
    • B. 0.27 At/Wb
    • C. 1200 At/Wb
    • D. More information is needed in order to find the reluctance.
    • Discuss
    • 2. A Hall effect sensor

    • Options
    • A. exists only in theory
    • B. is a noncontacting magnetic sensor
    • C. can operate only a few times before failure
    • D. produces very large voltages
    • Discuss
    • 3. The component that produces power in an electromagnetic generator is called the

    • Options
    • A. armature
    • B. field winding
    • C. commutator
    • D. brush
    • Discuss
    • 4. The unit for frequency is the

    • Options
    • A. hertz
    • B. ampere
    • C. watt
    • D. second
    • Discuss
    • 5. Add 21 mA and 8000 µA and express the result in milliamperes.

    • Options
    • A. 21.8 mA
    • B. 218 mA
    • C. 29 mA
    • D. 290 mA
    • Discuss
    • 6. Which electromagnetic device uses brushes and a commutator?

    • Options
    • A. A speaker
    • B. A dc generator
    • C. A relay
    • D. A solenoid
    • Discuss
    • 7. The Hall effect

    • Options
    • A. is a phenomenon with no practical applications
    • B. is used in various sensor applications
    • C. can develop potentials of thousands of volts
    • D. is the basis for solar cell operation
    • Discuss
    • 8. What are the effects of moving a closed wire loop through a magnetic field?

    • Options
    • A. A voltage is induced in the wire.
    • B. A current is induced in the wire.
    • C. The polarity across the wire depends on the direction of motion.
    • D. All of the above
    • Discuss
    • 9. Which electromagnetic device has a movable iron core called a plunger?

    • Options
    • A. A speaker
    • B. A dc generator
    • C. A relay
    • D. A solenoid
    • Discuss
    • 10. Which electromagnetic device has a flexible cone?

    • Options
    • A. A speaker
    • B. A dc generator
    • C. A relay
    • D. A solenoid
    • Discuss


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