Gibilisco - Impedance And Admittance

20 Questions | Total Attempts: 499

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Electrical Quizzes & Trivia

Questions and Answers
  • 1. 
    The square of an imaginary number
    • A. 

      Can never be negative.

    • B. 

      Can never be positive.

    • C. 

      Can be either positive or negative.

    • D. 

      Is equal to j.

  • 2. 
    A complex number
    • A. 

      Is the same thing as an imaginary number.

    • B. 

      Has a real-number part and an imaginary-number part.

    • C. 

      Is one-dimensional.

    • D. 

      Is a concept reserved for elite mathematicians.

  • 3. 
    What is the sum of 3 + j 7 and −3 − j 7?
    • A. 

      0 + j0

    • B. 

      6 + j14

    • C. 

      −6 − j14

    • D. 

      0 − j14

  • 4. 
    What is (−5 + j 7) − (4 − j5)?
    • A. 

      −1 + j2

    • B. 

      −9 − j2

    • C. 

      −1 − j2

    • D. 

      −9 + j12

  • 5. 
    What is the product (−4 − j 7)(6 − j2)?
    • A. 

      24 − j14

    • B. 

      −38 − j34

    • C. 

      −24 − j14

    • D. 

      −24 + j14

  • 6. 
    What is the magnitude of the vector 18 − j24?
    • A. 

      6

    • B. 

      21

    • C. 

      30

    • D. 

      52

  • 7. 
    The complex impedance value 5 + j0 represents
    • A. 

      A pure resistance.

    • B. 

      A pure inductance.

    • C. 

      A pure capacitance.

    • D. 

      An inductance combined with a capacitance.

  • 8. 
    The complex impedance value 0 − j22 represents
    • A. 

      A pure resistance.

    • B. 

      A pure inductance.

    • C. 

      A pure capacitance.

    • D. 

      An inductance combined with a resistance.

  • 9. 
    What is the absolute-value impedance of 3.0 − j 6.0?
    • A. 

      Z = 9.0 Ω

    • B. 

      Z = 3.0 Ω

    • C. 

      Z = 45 Ω

    • D. 

      Z = 6.7 Ω

  • 10. 
    What is the absolute-value impedance of 50 − j235?
    • A. 

      Z = 240 Ω

    • B. 

      Z = 58,000 Ω

    • C. 

      Z = 285 Ω

    • D. 

      Z =−185 Ω

  • 11. 
    If the center conductor of a coaxial cable is made to have a smaller diameter, all other thingsbeing equal, what will happen to the Zo of the transmission line?
    • A. 

      It will increase.

    • B. 

      It will decrease.

    • C. 

      It will not change.

    • D. 

      There is no way to determine this without knowing the actual dimensions.

  • 12. 
    If a device is said to have an impedance of Z = 100 Ω, you can reasonably expect that thisindicates
    • A. 

      R + jX = 100 + j0.

    • B. 

      R + jX = 0 + j100.

    • C. 

      R + jX = 100 + j100.

    • D. 

      The reactance and the resistance add up to 100 Ω.

  • 13. 
    Suppose a capacitor has a value of 0.050 µF at 665 kHz. What is the capacitive susceptance,stated as an imaginary number?
    • A. 

      BC = j4.79

    • B. 

      BC =−j4.79

    • C. 

      BC = j0.209

    • D. 

      BC =−j 0.209

  • 14. 
    An inductor has a value of 44 mH at 60 Hz. What is the inductive susceptance, stated as animaginary number?
    • A. 

      BL =−j0.060

    • B. 

      BL = j0.060

    • C. 

      BL =−j17

    • D. 

      BL = j17

  • 15. 
    Susceptance and conductance add to form
    • A. 

      Complex impedance.

    • B. 

      Complex inductance.

    • C. 

      Complex reactance.

    • D. 

      Complex admittance.

  • 16. 
    Absolute-value impedance is equal to the square root of which of the following?
    • A. 

      G^2+ B^2

    • B. 

      R^2+ X^2

    • C. 

      Zo

    • D. 

      Y^2+ R^2

  • 17. 
    Inductive susceptance is defined in
    • A. 

      Imaginary ohms.

    • B. 

      Imaginary henrys.

    • C. 

      Imaginary farads.

    • D. 

      Imaginary siemens.

  • 18. 
    Capacitive susceptance values can be defined by
    • A. 

      Positive real numbers.

    • B. 

      Negative real numbers.

    • C. 

      Positive imaginary numbers.

    • D. 

      Negative imaginary numbers.

  • 19. 
    Which of the following is false?
    • A. 

      BC = 1/XC.

    • B. 

      Complex impedance can be depicted as a vector.

    • C. 

      Characteristic impedance is complex.

    • D. 

      G = 1/R.

  • 20. 
    In general, as the absolute value of the impedance in a circuit increases,
    • A. 

      The flow of ac increases.

    • B. 

      The flow of ac decreases.

    • C. 

      The reactance decreases.

    • D. 

      The resistance decreases.

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