BEE FREE BEE Bachelor of Electrical Engineering DC and AC Circuit Analysis Questions and Answers 2 — Questions and Answers
Question 1: A 10 Ω resistor and a 20 Ω resistor are connected in parallel across a 40 V DC source. What is the total current drawn from the source?
- 6 A (Correct answer)
- 4 A
- 2 A
- 3 A
Correct answer: 6 A
Parallel equivalent resistance is (10×20)/(10+20) = 6.67 Ω, so I = 40/6.67 ≈ 6 A.
Question 2: In a series RLC AC circuit at resonance, which of the following is true?
- The impedance equals the resistance only (Correct answer)
- The impedance is at its maximum value
- The current is at its minimum value
- The power factor is zero
Correct answer: The impedance equals the resistance only
At resonance the inductive and capacitive reactances cancel, leaving only the resistance as the total impedance.
Question 3: What is the phase angle between voltage and current in a purely capacitive AC circuit?
- Current leads voltage by 90° (Correct answer)
- Voltage leads current by 90°
- They are in phase
- Current leads voltage by 45°
Correct answer: Current leads voltage by 90°
In a purely capacitive circuit, the current leads the voltage by 90 degrees.
Question 4: A DC circuit has three resistors of 4 Ω, 6 Ω, and 12 Ω connected in parallel. What is the equivalent resistance?
- 2 Ω (Correct answer)
- 4 Ω
- 3 Ω
- 1.5 Ω
Correct answer: 2 Ω
1/Req = 1/4 + 1/6 + 1/12 = 6/12 = 0.5, so Req = 2 Ω.
Question 5: In an AC circuit, the real power consumed by a load with an impedance of 5∠60° Ω carrying 4 A rms is:
- 40 W (Correct answer)
- 80 W
- 20 W
- 69.3 W
Correct answer: 40 W
Real power P = I²R = 16 × 5cos60° = 16 × 2.5 = 40 W.
Question 6: According to Kirchhoff's Voltage Law (KVL), the algebraic sum of all voltages around any closed loop in a circuit is:
- Zero (Correct answer)
- Equal to the source voltage
- Equal to the total resistance times current
- Dependent on the number of nodes
Correct answer: Zero
KVL states that the sum of all voltage rises and drops around any closed loop must equal zero.
BEE FREE BEE Bachelor of Electrical Engineering DC and AC Circuit Analysis Questions and Answers 2
A 10 Ω resistor and a 20 Ω resistor are connected in parallel across a 40 V DC source.
What is the total current drawn from the source?