All Free Electrical Engineering MCQs with Answers
Every Electrical Engineering question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
3,143 questions · page 5 of 158
- A. 25 Ω
- B. 500 Ω
- C. 100 Ω
- D. 20 Ω
Explanation: Removing one of five parallel resistors leaves four 100 Ω resistors in parallel. Their equivalent resistance is 100/4 = 25 Ω.
Correct answer: 25 Ω- A. 22 mA
- B. 120 mA
- C. 220 mA
- D. 50 mA
Explanation: The parallel network voltage is V = I_total R_total = 0.12 × 50 = 6 V. Thus the 270 Ω branch current is 6/270 ≈ 22 mA.
Correct answer: 22 mA- A. 790 Ω
- B. 470 Ω
- C. 60 Ω
- D. 30 Ω
Explanation: For parallel resistors, conductances add: 1/Rt = 1/470 + 1/220 + 1/100, giving Rt ≈ 60 Ω.
Correct answer: 60 Ω- A. 12.5 Ω
- B. 200 Ω
- C. 20 KΩ
- D. 50 Ω
Explanation: The total equivalent resistance is V/I = 10 V/2 mA = 5 kΩ. With four equal resistors in parallel, each resistor is four times the…
Correct answer: 20 KΩ- A. greater than 1.6 kΩ
- B. greater than 120 but less than 1.6 kΩ
- C. less than 120 but greater than 100 Ω
- D. less than 100 Ω
Explanation: A parallel combination is always less than its smallest branch resistance, so the result must be below 120 Ω.
Correct answer: less than 120 but greater than 100 Ω- A. 18 W
- B. 1.5 W
- C. 48 W
- D. 72 W
Explanation: Four 8 Ω speakers in parallel have an equivalent resistance of 8/4 = 2 Ω. Thus the required power is P = V²/R = 12²/2 = 72 W.
Correct answer: 72 W- A. a drop in source voltage
- B. an open resistor
- C. an increase in source voltage
- D. either a drop in source voltage or an open resistor
Explanation: For a fixed parallel network, total current increases when the source voltage increases, since I = V/Rt.
Correct answer: an increase in source voltage- A. 2.3 A
- B. 780 mA
- C. 47 mA
- D. 7.06 A
Explanation: Three identical 47 Ω branches in parallel have an equivalent resistance of 47/3 ≈ 15.7 Ω. The source current is therefore 110/15.7 ≈ 7.06 A.
Correct answer: 7.06 A- A. 48 mA
- B. 12 mA
- C. 0 A
- D. 3 mA
Explanation: In a parallel circuit, each branch has the same source voltage, so the current in an unchanged branch remains 12 mA when another branch…
Correct answer: 12 mA- A. 2.2 A
- B. 137 mA
- C. 1.8 A
- D. 9.09 A
Explanation: In a parallel connection, each bulb receives the full 110 V. Using I = P/V gives I = 200/110 ≈ 1.8 A, so the current is independent of the…
Correct answer: 1.8 A- A. the remaining two will glow dimmer
- B. the remaining two will glow brighter
- C. the remaining two will not light
- D. the remaining two will glow with the same brightness as before
Explanation: Each parallel light remains connected directly across the 120 V source, so one failed branch does not change the voltage across the other…
Correct answer: the remaining two will glow with the same brightness as before- A. remains the same
- B. decreases by the value of the added resistor
- C. increases by the value of the added resistor
- D. decreases
Explanation: Adding a resistor in parallel provides an additional path for current, increasing total conductance.
Correct answer: decreases- A. 25 mA
- B. 100 mA
- C. 6.25 mA
- D. 200 mA
Explanation: Four equal parallel resistors have a combined resistance of 600 Ω, so each resistor is 4 × 600 = 2400 Ω.
Correct answer: 6.25 mA- A. 1 A
- B. 7 A
- C. unknown
- D. the larger of the two
Explanation: Kirchhoff’s current law requires the total current entering a junction to equal the total current leaving it.
Correct answer: 7 A- A. 50 mA
- B. 70 mA
- C. 120 mA
- D. 40 mA
Explanation: The branch currents in a parallel circuit add to the total current. The missing branch is 120 − 40 − 10 = 70 mA.
Correct answer: 70 mA- A. 1.2 W
- B. 4.8 W
- C. 0.3 W
- D. 12 W
Explanation: Power in parallel branches is additive because the source supplies the sum of the branch powers. Hence, total power = 4 × 1.2 = 4.8 W.
Correct answer: 4.8 W- A. ampere-hour
- B. watt
- C. joule
- D. coulomb
Explanation: Electric charge, or quantity of electricity, is measured in coulombs. Ampere-hour is also a charge unit in practical battery calculations…
Correct answer: coulomb- A. M
- B. M/2
- C. 2 M
- D. M/4
Explanation: Magnetic moment equals pole strength multiplied by magnetic length. Cutting the magnet into two equal pieces makes the pole strength or…
Correct answer: M/2- A. pole strength
- B. universal constant
- C. scalar quantity
- D. vector quantity
Explanation: Magnetic moment has both magnitude and direction, with its direction conventionally from the south pole to the north pole inside the…
Correct answer: vector quantity- A. circular
- B. triangular
- C. rectangular
- D. none of the above
Explanation: Hard magnetic materials retain magnetism and require a large coercive force, producing a wide, nearly rectangular hysteresis loop.
Correct answer: rectangular