G5 – ELECTRICAL PRINCIPLES [3 Exam Questions – 3 Groups] Flashcards
What is impedance?
A. The electric charge stored by a capacitor
B. The inverse of resistance
C. The opposition to the flow of current in an AC circuit
D. The force of repulsion between two similar electric fields
G5A01 (C)
C. The opposition to the flow of current in an AC circuit
What is reactance?
A. Opposition to the flow of direct current caused by resistance
B. Opposition to the flow of alternating current caused by capacitance or inductance
C. A property of ideal resistors in AC circuits
D. A large spark produced at switch contacts when an inductor is de-energized
G5A02 (B)
B. Opposition to the flow of alternating current caused by capacitance or inductance
Which of the following causes opposition to the flow of alternating current in an inductor?
A. Conductance
B. Reluctance
C. Admittance
D. Reactance
G5A03 (D)
D. Reactance
Which of the following causes opposition to the flow of alternating current in a capacitor?
A. Conductance
B. Reluctance
C. Reactance
D. Admittance
G5A04 (C)
C. Reactance
How does an inductor react to AC?
A. As the frequency of the applied AC increases, the reactance decreases
B. As the amplitude of the applied AC increases, the reactance increases
C. As the amplitude of the applied AC increases, the reactance decreases
D. As the frequency of the applied AC increases, the reactance increases
G5A05 (D)
D. As the frequency of the applied AC increases, the reactance increases
How does a capacitor react to AC?
A. As the frequency of the applied AC increases, the reactance decreases
B. As the frequency of the applied AC increases, the reactance increases
C. As the amplitude of the applied AC increases, the reactance increases
D. As the amplitude of the applied AC increases, the reactance decreases
G5A06 (A)
A. As the frequency of the applied AC increases, the reactance decreases
What happens when the impedance of an electrical load is equal to the output impedance of a power source, assuming both impedances are resistive?
A. The source delivers minimum power to the load
B. The electrical load is shorted
C. No current can flow through the circuit
D. The source can deliver maximum power to the load
G5A07 (D)
D. The source can deliver maximum power to the load
What is one reason to use an impedance matching transformer?
A. To minimize transmitter power output
B. To maximize the transfer of power
C. To reduce power supply ripple
D. To minimize radiation resistance
G5A08 (B)
B. To maximize the transfer of power
What unit is used to measure reactance?
A. Farad
B. Ohm
C. Ampere
D. Siemens
G5A09 (B)
B. Ohm
Which of the following devices can be used for impedance matching at radio frequencies?
A. A transformer
B. A Pi-network
C. A length of transmission line
D. All these choices are correct
G5A10 (D)
D. All these choices are correct
Which of the following describes one method of impedance matching between two AC circuits?
A. Insert an LC network between the two circuits
B. Reduce the power output of the first circuit
C. Increase the power output of the first circuit
D. Insert a circulator between the two circuits
G5A11 (A)
A. Insert an LC network between the two circuits
What dB change represents a factor of two increase or decrease in power?
A. Approximately 2 dB
B. Approximately 3 dB
C. Approximately 6 dB
D. Approximately 12 dB
G5B01 (B)
B. Approximately 3 dB
How does the total current relate to the individual currents in each branch of a purely resistive parallel circuit?
A. It equals the average of each branch current
B. It decreases as more parallel branches are added to the circuit
C. It equals the sum of the currents through each branch
D. It is the sum of the reciprocal of each individual voltage drop
G5B02 (C)
C. It equals the sum of the currents through each branch
How many watts of electrical power are used if 400 VDC is supplied to an 800 ohm load? A. 0.5 watts B. 200 watts C. 400 watts D. 3200 watts
G5B03 (B)
B. 200 watts
How many watts of electrical power are used by a 12 VDC light bulb that draws 0.2 amperes?
A. 2.4 watts
B. 24 watts
C. 6 watts
D. 60 watts
G5B04 (A)
A. 2.4 watts
How many watts are dissipated when a current of 7.0 milliamperes flows through a 1250 ohm resistance?
A. Approximately 61 milliwatts
B. Approximately 61 watts
C. Approximately 11 milliwatts
D. Approximately 11 watts
G5B05 (A)
B. Approximately 61 watts
What is the output PEP from a transmitter if an oscilloscope measures 200 volts peak-to-peak across a 50 ohm dummy load connected to the transmitter output?
A. 1.4 watts
B. 100 watts
C. 353.5 watts
D. 400 watts
G5B06 (B)
B. 100 watts