Topic G5A Quick Review Audio

G5A01:

What is impedance?

  1. The electric charge stored by a capacitor
  2. The inverse of resistance
  3. The opposition to the flow of current in an AC circuit
  4. The force of repulsion between two similar electric fields

G5A02:

What is reactance?

  1. Opposition to the flow of direct current caused by resistance
  2. Opposition to the flow of alternating current caused by capacitance or inductance
  3. A property of ideal resistors in AC circuits
  4. A large spark produced at switch contacts when an inductor is de-energized

G5A03:

Which of the following causes opposition to the flow of alternating current in an inductor?

  1. Conductance
  2. Reluctance
  3. Admittance
  4. Reactance

G5A04:

Which of the following causes opposition to the flow of alternating current in a capacitor?

  1. Conductance
  2. Reluctance
  3. Reactance
  4. Admittance

G5A05:

How does an inductor react to AC?

  1. As the frequency of the applied AC increases, the reactance decreases
  2. As the amplitude of the applied AC increases, the reactance increases
  3. As the amplitude of the applied AC increases, the reactance decreases
  4. As the frequency of the applied AC increases, the reactance increases

G5A06:

How does a capacitor react to AC?

  1. As the frequency of the applied AC increases, the reactance decreases
  2. As the frequency of the applied AC increases, the reactance increases
  3. As the amplitude of the applied AC increases, the reactance increases
  4. As the amplitude of the applied AC increases, the reactance decreases

G5A07:

What happens when the impedance of an electrical load is equal to the output impedance of a power source, assuming both impedances are resistive?

  1. The source delivers minimum power to the load
  2. The electrical load is shorted
  3. No current can flow through the circuit
  4. The source can deliver maximum power to the load

G5A08:

What is one reason to use an impedance matching transformer?

  1. To minimize transmitter power output
  2. To maximize the transfer of power
  3. To reduce power supply ripple
  4. To minimize radiation resistance

G5A09:

What unit is used to measure reactance?

  1. Farad
  2. Ohm
  3. Ampere
  4. Siemens

G5A10:

Which of the following devices can be used for impedance matching at radio frequencies?

  1. A transformer
  2. A Pi-network
  3. A length of transmission line
  4. All these choices are correct

G5A11:

Which of the following describes one method of impedance matching between two AC circuits?

  1. Insert an LC network between the two circuits
  2. Reduce the power output of the first circuit
  3. Increase the power output of the first circuit
  4. Insert a circulator between the two circuits