BEE Electric Circuits 2 — Questions and Answers
Question 1: A 10 Ω resistor and a 40 Ω resistor are connected in parallel. What is the equivalent resistance?
- 8 Ω (Correct answer)
- 50 Ω
- 25 Ω
- 4 Ω
Correct answer: 8 Ω
Parallel resistance: 1/Req = 1/10 + 1/40 = 5/40, so Req = 8 Ω.
Question 2: Which of the following best describes a node in circuit analysis?
- A point where two or more circuit elements meet (Correct answer)
- A closed loop in a circuit
- A component that stores energy
- A voltage source terminal
Correct answer: A point where two or more circuit elements meet
A node is any point in a circuit where two or more elements are connected together.
Question 3: A capacitor of 100 µF is charged to 50 V. How much energy is stored?
- 0.125 J (Correct answer)
- 0.25 J
- 5000 J
- 0.05 J
Correct answer: 0.125 J
Energy stored in a capacitor: E = ½CV² = ½ × 100×10⁻⁶ × 50² = 0.125 J.
Question 4: In a series RLC circuit at resonance, the impedance is purely:
- Resistive (Correct answer)
- Inductive
- Capacitive
- Zero
Correct answer: Resistive
At resonance, inductive and capacitive reactances cancel, leaving only the resistive component.
Question 5: What does the time constant τ represent in an RC circuit?
- The time for the capacitor to charge to 63.2% of its final value (Correct answer)
- The time to fully charge the capacitor
- The time for the voltage to reach its peak
- Half the period of oscillation
Correct answer: The time for the capacitor to charge to 63.2% of its final value
The time constant τ = RC is the time required for the capacitor voltage to reach approximately 63.2% of its final steady-state value.
Question 6: Applying KVL to a loop, you sum all voltage drops and rises. The result must equal:
- Zero (Correct answer)
- The supply voltage
- The total resistance
- The loop current
Correct answer: Zero
Kirchhoff's Voltage Law states that the algebraic sum of all voltages around any closed loop equals zero.
Question 7: Two capacitors of 6 µF and 3 µF are connected in series. What is the equivalent capacitance?
- 2 µF (Correct answer)
- 9 µF
- 4.5 µF
- 18 µF
Correct answer: 2 µF
Series capacitance: 1/Ceq = 1/6 + 1/3 = 1/2, so Ceq = 2 µF.
BEE Electric Circuits 2
A 10 Ω resistor and a 40 Ω resistor are connected in parallel.
What is the equivalent resistance?