Questions - Capacitors, Inductors and Resonance 

Question file 9


  1. The total capacitance of two or more capacitors in series is:             STUDY NOTES 
    1. always less than that of the smallest capacitor
    2. always greater than that of the largest capacitor                    QUESTIONS WITHOUT ANSWERS 
    3. found by adding each of the capacitances together
    4. found by adding the capacitances together and dividing by their total number
    ========= Answer is a =========
  2. Filter capacitors in power supplies are sometimes connected in series to:
    1. withstand a greater voltage than a single capacitor can withstand
    2. increase the total capacity
    3. reduce the ripple voltage further
    4. resonate the filter circuit
    ========= Answer is a =========
  3. A radio component is identified as a capacitor if its value is measured in:
    1. microvolts
    2. millihenrys
    3. megohms
    4. microfarads
    ========= Answer is d =========
  4. Two metal plates separated by air form a 0.001 uF capacitor. Its value may be changed to 0.002 uF by:
    1. bringing the metal plates closer together
    2. making the plates smaller in size
    3. moving the plates apart
    4. touching the two plates together
    ========= Answer is a =========
  5. The material separating the plates of a capacitor is the:
    1. dielectric
    2. semiconductor
    3. resistor
    4. lamination
    ========= Answer is a =========
  6. Three 15 picofarad capacitors are wired in parallel. The value of the combination is:
    1. 45 picofarad
    2. 18 picofarad
    3. 12 picofarad
    4. 5 picofarad
    ========= Answer is a =========
  7. Capacitors and inductors oppose an alternating current. This is known as:
    1. resistance
    2. resonance
    3. conductance
    4. reactance
    ========= Answer is d =========
  8. The reactance of a capacitor increases as the:
    1. frequency increases
    2. frequency decreases
    3. applied voltage increases
    4. applied voltage decreases
    ========= Answer is b =========
  9. The reactance of an inductor increases as the:
    1. frequency increases
    2. frequency decreases
    3. applied voltage increases
    4. applied voltage decreases
    ========= Answer is a =========
  10. Increasing the number of turns on an inductor will make its inductance:
    1. decrease
    2. increase
    3. remain unchanged
    4. become resistive
    ========= Answer is b =========
  11. The unit of inductance is the:
    1. farad
    2. henry
    3. ohm
    4. reactance
    ========= Answer is b =========
  12. Two 20 uH inductances are connected in series. The total inductance is:
    1. 10 uH
    2. 20 uH
    3. 40 uH
    4. 80 uH
    ========= Answer is c =========
  13. Two 20 uH inductances are connected in parallel. The total inductance is:
    1. 10 uH
    2. 20 uH
    3. 40 uH
    4. 80 uH
    ========= Answer is a =========
  14. A toroidal inductor is one in which the:
    1. windings are wound on a closed ring of magnetic material
    2. windings are air-spaced
    3. windings are wound on a ferrite rod
    4. inductor is enclosed in a magnetic shield
    ========= Answer is a =========
  15. A transformer with 100 turns on the primary winding and 10 turns on the secondary winding is connected to 230 volt AC mains. The voltage across the secondary is:
    1. 10 volt
    2. 23 volt
    3. 110 volt
    4. 2300 volt
    ========= Answer is b =========
  16. An inductor and a capacitor are connected in series. At the resonant frequency the resulting impedance is:
    1. maximum
    2. minimum
    3. totally reactive
    4. totally inductive
    ========= Answer is b =========
  17. An inductor and a capacitor are connected in parallel. At the resonant frequency the resulting impedance is:
    1. maximum
    2. minimum
    3. totally reactive
    4. totally inductive
    ========= Answer is a =========
  18. An inductor and a capacitor form a resonant circuit. The capacitor value is increased by four times. The resonant frequency will:
    1. increase by four times
    2. double
    3. decrease to half
    4. decrease to one quarter
    ========= Answer is c =========
  19. An inductor and a capacitor form a resonant circuit. If the value of the inductor is decreased by a factor of four, the resonant frequency will:
    1. increase by a factor of four
    2. increase by a factor of two
    3. decrease by a factor of two
    4. decrease by a factor of four
    ========= Answer is b =========
  20. A "high Q" resonant circuit is one which:
    1. carries a high quiescent current
    2. is highly selective
    3. has a wide bandwidth
    4. uses a high value inductance
    ========= Answer is b =========