Gibilisco - Inductive Reactance

18 Questions | Total Attempts: 371

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Gibilisco - Inductive Reactance

Questions and Answers
  • 1. 
    As the number of turns in a coil that carries ac increases without limit, the current in the coilwill
    • A. 

      Eventually become very large.

    • B. 

      Stay the same.

    • C. 

      Decrease, approaching zero.

    • D. 

      Be stored in the core material.

  • 2. 
    As the number of turns in a coil increases, the reactance at a constant frequency
    • A. 

      Increases.

    • B. 

      Decreases.

    • C. 

      Stays the same.

    • D. 

      Is stored in the core material.

  • 3. 
    As the frequency of an ac wave gets lower, the value of XL for a particular coil of wire
    • A. 

      Increases.

    • B. 

      Decreases.

    • C. 

      Stays the same.

    • D. 

      Depends on the voltage.

  • 4. 
    Suppose a coil has an inductance of 100 mH. What is the reactance at a frequency of 1000Hz?
    • A. 

      0.628 Ω

    • B. 

      6.28 Ω

    • C. 

      62.8 Ω

    • D. 

      628 Ω

  • 5. 
    Suppose a coil shows an inductive reactance of 200 Ω at 500 Hz. What is its inductance?
    • A. 

      0.637 H

    • B. 

      628 H

    • C. 

      63.7 mH

    • D. 

      628 mH

  • 6. 
    Imagine a 400-µH inductor with a reactance of 33 Ω. What is the frequency?
    • A. 

      13 kHz

    • B. 

      0.013 kHz

    • C. 

      83 kHz

    • D. 

      83 MHz

  • 7. 
    Suppose an inductor has XL = 555 Ω at f = 132 kHz. What is L?
    • A. 

      670 mH

    • B. 

      670 µH

    • C. 

      460 mH

    • D. 

      460 µH

  • 8. 
    Suppose a coil has L = 689 µH at f = 990 kHz. What is XL?
    • A. 

      682 Ω

    • B. 

      4.28 Ω

    • C. 

      4.28 kΩ

    • D. 

      4.28 MΩ

  • 9. 
    Suppose an inductor has L = 88 mH with XL = 100 Ω. What is f?
    • A. 

      55.3 kHz

    • B. 

      55.3 Hz

    • C. 

      181 kHz

    • D. 

      181 Hz

  • 10. 
    Each point in the RL plane
    • A. 

      Corresponds to a unique resistance.

    • B. 

      Corresponds to a unique inductance.

    • C. 

      Corresponds to a unique combination of resistance and inductive reactance.

    • D. 

      Corresponds to a unique combination of resistance and inductance.

  • 11. 
    If the resistance R and the inductive reactance XL both are allowed to vary from zero tounlimited values, but are always in the ratio 3:1, the points in the RL plane for all the resultingimpedances will lie along
    • A. 

      A vector pointing straight up.

    • B. 

      A vector pointing east.

    • C. 

      A circle.

    • D. 

      A ray of indefinite length, pointing outward from the origin.

  • 12. 
    Each specific complex impedance value defined in the form R + jXL
    • A. 

      Corresponds to a specific point in the RL plane.

    • B. 

      Corresponds to a specific inductive reactance.

    • C. 

      Corresponds to a specific resistance.

    • D. 

      All of the above are true.

  • 13. 
    A vector is defined as a mathematical quantity that has
    • A. 

      Magnitude and direction.

    • B. 

      Resistance and inductance.

    • C. 

      Resistance and reactance.

    • D. 

      Inductance and reactance.

  • 14. 
    In an RL circuit, as the ratio of inductive reactance to resistance (XL/R) decreases, the phaseangle
    • A. 

      Increases.

    • B. 

      Decreases.

    • C. 

      Stays the same.

    • D. 

      Becomes alternately positive and negative.

  • 15. 
    In a circuit containing inductive reactance but no resistance, the phase angle is
    • A. 

      Constantly increasing.

    • B. 

      Constantly decreasing.

    • C. 

      Equal to 0°.

    • D. 

      Equal to 90°.

  • 16. 
    If the inductive reactance and the resistance in an RL circuit are equal (as expressed in ohms),then what is the phase angle?
    • A. 

    • B. 

      45°

    • C. 

      90°

    • D. 

      It depends on the actual values of the resistance and the inductive reactance.

  • 17. 
    Consider an RL circuit that consists of a 100-µH inductor and a 100-Ω resistor. What is thephase angle at a frequency of 200 kHz?
    • A. 

      45.0°

    • B. 

      51.5°

    • C. 

      38.5°

    • D. 

      There isn’t enough data given to calculate it.

  • 18. 
    Suppose an RL circuit has an inductance of 88 mH, and the resistance is 95 Ω. At 800 Hz,what is the phase angle?
    • A. 

      78°

    • B. 

      12°

    • C. 

      43°

    • D. 

      47°

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