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Home Electrical Engineering Magnetism and Electromagnetism Comments

  • Question
  • When the north poles of two bar magnets are brought close together, there will be


  • Options
  • A. no force
  • B. a downward force
  • C. a force of attraction
  • D. a force of repulsion

  • Correct Answer
  • a force of repulsion 


  • Magnetism and Electromagnetism problems


    Search Results


    • 1. What is the magnetomotive force in a 75-turn coil of wire when there are 4 A of current through it?

    • Options
    • A. 18.75 At
    • B. 30 At
    • C. 300 At
    • D. 187 At
    • Discuss
    • 2. The ability of a material to remain magnetized after removal of the magnetizing force is known as

    • Options
    • A. permeability
    • B. reluctance
    • C. hysteresis
    • D. retentivity
    • Discuss
    • 3. When the speed at which a conductor is moved through a magnetic field is increased, the induced voltage

    • Options
    • A. increases
    • B. decreases
    • C. remains constant
    • D. reaches zero
    • Discuss
    • 4. The direction of a magnetic field within a magnet is

    • Options
    • A. from south to north
    • B. from north to south
    • C. back to front
    • D. front to back
    • Discuss
    • 5. If the cross-sectional area of a magnetic field increases, but the flux remains the same, the flux density

    • Options
    • A. increases
    • B. decreases
    • C. remains the same
    • D. doubles
    • Discuss
    • 6. What is the magnetomotive force (mmf) of a wire with 8 turns carrying three amperes of current?

    • Options
    • A. 2,400 At
    • B. 240 At
    • C. 24 At
    • D. 2.4 At
    • Discuss
    • 7. What is the flux density in a magnetic field in which the flux in 0.1 m2 is 600 µWb?

    • Options
    • A. 6,000 µT
    • B. 600 µT
    • C. 600 T
    • D. 6 T
    • Discuss
    • 8. The induced voltage across a coil with 250 turns that is located in a magnetic field that is changing at a rate of 8 Wb/s is

    • Options
    • A. 1,000 V
    • B. 2,000 V
    • C. 31.25 V
    • D. 3,125 V
    • Discuss
    • 9. The unit for reluctance is

    • Options
    • A. tesla
    • B. At/Wb
    • C. At/m
    • D. Wb
    • Discuss
    • 10. If a loop in a basic dc generator suddenly begins rotating at a faster speed, the induced voltage

    • Options
    • A. remains unchanged
    • B. reverses polarity
    • C. increases
    • D. decreases
    • Discuss


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