NETA - InterNational Electrical Testing Association Certified Technicians AC/DC Theory and Circuits Questions and Answers

Question 1

A technician is analyzing a series AC circuit operating at 60 Hz.
The circuit contains a resistor (R) of 8 ohms, an inductor with an inductive reactance (XL) of 10 ohms, and a capacitor with a capacitive reactance (XC) of 4 ohms.
What is the total impedance (Z) of this circuit?

Accepted Answer

10.0 ohms

Answer

14.0 ohms

Answer

22.0 ohms

Answer

6.0 ohms

Question 2

In an AC power system, which of the following best describes the relationship between true power (P), reactive power (Q), and apparent power (S)?

Accepted Answer

Apparent power is the vector sum of true power and reactive power.

Answer

Apparent power is the algebraic sum of true power and reactive power.

Answer

True power is the vector sum of apparent power and reactive power.

Answer

Reactive power is always greater than apparent power.

Question 3

A technician closes a switch to apply a DC voltage source to a circuit containing only a resistor and a large inductor in series. Immediately at the instant the switch is closed (t=0), how does the inductor behave?

Accepted Answer

As an open circuit, with maximum voltage drop.

Answer

As a short circuit, with maximum current flow.

Answer

As a closed switch with no voltage drop.

Answer

As a resistor equal to its DC resistance.

Question 4

A field service report notes that a three-phase transformer is consistently running hotter than its nameplate rating would suggest, despite the load current being within limits. Which of the following is the most likely cause for the overheating?

Accepted Answer

High levels of harmonic distortion

Answer

Low system frequency

Answer

Excessive capacitive loading

Answer

A leading power factor

Question 5

A technician uses a power quality analyzer on an AC circuit and measures the true power as 4.0 kW and the apparent power as 5.0 kVA. What is the power factor of this circuit?

Accepted Answer

0.80

Answer

1.25

Answer

0.75

Answer

0.90

Question 6

According to Kirchhoff's Current Law (KCL), what is the current (I_total) entering a junction if three branches leaving the junction have currents of 2 A, 5 A, and 3.5 A?

Accepted Answer

10.5 A

Answer

7.0 A

Answer

Cannot be determined without voltage

Answer

5.5 A