Question 1
What is the main function of an arc-fault circuit interrupter (AFCI) in residential wiring?
Question 2
A shop has several induction motors that cause a lagging power factor. Which device is commonly installed to improve the power factor?
Question 3
What is the unit of electrical power commonly used in residential installations?
Question 4
A shop owner installs several large induction motors and notices an increase in reactive current on the utility bill. What device is commonly added to improve power factor?
Question 5
Calculate the power factor if True Power is 8 kW and Apparent Power is 10 kVA.
Question 6
A single-phase motor nameplate shows 240 V, 10 A, power factor 0.8. Approximately how much apparent power (in volt-amperes) does it draw at rated load?
Question 7
Which statement best describes voltage?
Question 8
A single-phase 240 V load draws 12 A. Approximately what is its power rating?
Question 9
Two 60 W, 120 V lamps are connected in parallel on a 120 V circuit. What is the total power drawn by the lamps?
Question 10
A 3 kW water heater operates on 240 V single-phase. What is the approximate current drawn by the heater?
Question 11
A 240 V single-phase motor nameplate shows a full-load current of 12 A. What is the approximate running power if the power factor is 0.9?
Question 12
In an industrial setting with multiple large motors, the facility experiences low power factor penalties from the utility. Which correction is MOST commonly used?
Question 13
Which of the following best describes power factor in an AC circuit?
Question 14
A circuit draws $12.5 \text{ A}$ from a $240\text{ V}$ AC source with a power factor of $0.8$ lagging. What is the apparent power ($S$) for this circuit?
Question 15
What is the unit of measurement for **reactive power** in an AC circuit?
Question 16
Which of the following is the most likely cause of a low power factor (PF) in a large commercial facility?
Question 17
Which of the following is the most effective method for correcting a severely lagging power factor in a large industrial plant?
Question 18
You measure 10 A of current on a 120 V branch circuit supplying several receptacles. What is the apparent power on the circuit assuming a power factor of 1?
Question 19
Two 600 W lighting loads are connected to a 120 V branch circuit. What is the total apparent power of these loads?
Question 20
What describes the power factor of a circuit where the current lags the voltage by 90 degrees?
Question 21
In the power triangle, what does 'VAR' represent?
Question 22
Calculate the true power (P) of a circuit with 120V applied, drawing 10A, with a power factor of 0.85.
Question 23
What is the primary cause of a low power factor in an industrial facility?
Question 24
A 240V motor consumes 3000W of true power and the apparent power is 4000VA. What is the power factor?