Neiep 600 Final Exam 2026 Complete Practice Test – 210+ Multiple Choice Questions With Correct Answers And Rationales

NEIEP 600 FINAL EXAM 2026 COMPLETE PRACTICE TEST – 210+ MULTIPLE CHOICE QUESTIONS WITH CORRECT ANSWERS AND RATIONALES Question 1 In capacitors, what is the purpose of the dielectric? A. To increase capacitance B. To prevent arcing within the capacitor C. To reduce resistance D. To store electrons Correct Answer: B. To prevent arcing within the capacitor Explanation: The dielectric is an insulating material between capacitor plates that prevents arcing (current jumping between plates) while allowing electrostatic charge storage. ________________________________________ Question 2 Which of the following is true about capacitors in AC circuits? A. Voltage leads current B. Current leads voltage all the time C. Current and voltage are in phase D. Current lags voltage Correct Answer: B. Current leads voltage all the time Explanation: In a purely capacitive AC circuit, current leads voltage by 90 degrees. This is opposite of an inductive circuit where current lags voltage. ________________________________________ Question 3 What describes a capacitor's ability to store an electrical charge? A. Resistance B. Inductance C. Capacitance D. Impedance Correct Answer: C. Capacitance Explanation: Capacitance (measured in farads) is the ability of a capacitor to store an electrical charge. It is determined by plate area, distance between plates, and dielectric material. ________________________________________ Question 4 Which of the following statements is correct about polarized electrolytic capacitors? A. Voltage polarity does not matter B. Voltage polarity must be correct C. They can be used in AC circuits only D. They have no dielectric Correct Answer: B. Voltage polarity must be correct Explanation: Polarized electrolytic capacitors have a positive and negative terminal. Reverse polarity can cause dielectric breakdown, overheating, and explosion. ________________________________________ Question 5 What is the time constant for a circuit with 150k ohms and 2 microfarad capacitor? A. 0.3 seconds B. 0.03 seconds C. 3.0 seconds D. 300 seconds Correct Answer: A. 0.3 seconds *Explanation: Time constant (τ) = R × C = 150,000 Ω × 0.000002 F = 0.3 seconds.* ________________________________________ Question 6 If frequency is increased in a capacitive circuit, what will happen to capacitive reactance? A. Capacitive reactance will increase B. Capacitive reactance will decrease C. Capacitive reactance will stay the same D. Capacitive reactance will become zero Correct Answer: B. Capacitive reactance will decrease *Explanation: Capacitive reactance (Xc = 1/(2πfC)) is inversely proportional to frequency. As frequency increases, Xc decreases.* ________________________________________ Question 7 What happens in a DC circuit when the capacitor voltage equals the source voltage? A. Current flow stops in the circuit B. Current flow is maximum C. The capacitor is shorted D. The capacitor discharges Correct Answer: A. Current flow stops in the circuit Explanation: When fully charged, capacitor voltage equals source voltage, no potential difference exists, so current flow stops (open circuit condition). ________________________________________ Question 8 In a DC circuit, which is correct about capacitors the instant when power is applied? A. Current is zero B. Current is maximum C. Voltage is maximum D. The capacitor is fully charged Correct Answer: B. Current is maximum Explanation: At the instant power is applied, the capacitor acts as a short circuit (zero voltage, maximum current). Current then decreases exponentially as the capacitor charges. ________________________________________ Question 9 What is the total capacitance of three capacitors (100 µF, 100 µF, 50 µF) connected in parallel? A. 25 µF B. 150 µF C. 250 µF D. 500 µF Correct Answer: C. 250 µF *Explanation: Capacitors in parallel add: Ctotal = 100 + 100 + 50 = 250 µF.* ________________________________________ Question 10 If a circuit has a capacitor of 5 microfarads and a source voltage of 120 volts DC through a resistance of 200k ohms, how long will it take to fully charge? A. 0.5 seconds B. 1 second C. 5 seconds D. 10 seconds Correct Answer: C. 5 seconds *Explanation: One time constant τ = R × C = 200,000 Ω × 0.000005 F = 1 second. A capacitor is considered fully charged after 5 time constants = 5 seconds.* ________________________________________ Question 11 Which statement best describes one time constant of a capacitor? A. The time it takes to charge to 63.2% of applied voltage B. The time it takes to charge to 100% of applied voltage C. The time it takes to discharge to 50% of applied voltage D. The time it takes to reach maximum current Correct Answer: A. The time it takes to charge to 63.2% of applied voltage *Explanation: One time constant (τ = RC) charges the capacitor to 63.2% of the source voltage. It takes 5τ to reach full charge (99.3%).* ________________________________________ Question 12 What is the capacitive reactance of a 10 µF capacitor at 60 Hz? A. 26.5 ohms B. 265 ohms C. 2,650 ohms D. 26,500 ohms Correct Answer: B. 265 ohms *Explanation: Xc = 1/(2πfC) = 1/(2 × 3.14 × 60 × 0.00001) = 1/(0.003768) = 265.3 ohms.* ________________________________________ Question 13 Two capacitors (100 µF and 300 µF) are connected in series. What is the total capacitance?