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Question 1. Which SI unit is used to measure electric charge? A) Coulomb B) Volt C) Ampere D) Watt Answer: A Explanation: The Coulomb (C) is the SI unit of electric charge, representing the amount of charge transferred by a steady current of one ampere in one second. Question 2. What is the SI unit of electric current? A) Coulomb B) Volt C) Ampere D) Ohm Answer: C Explanation: The Ampere (A) is the SI unit of electric current, measuring the flow of electric charge per second.
Question 3. Which of the following equations correctly relates power, voltage, and current? A) P = V / I B) P = V × I C) P = I / V D) P = V + I Answer: B Explanation: Power (P) in an electrical circuit is given by P = V × I, representing the rate at which energy is transferred or converted. Question 4. How is electrical energy calculated from power? A) E = P / t B) E = P × t C) E = V × I D) E = V / I Answer: B Explanation: Energy (E) is obtained by multiplying power (P) by time (t), i.e., E = P × t, representing total energy consumed or transferred over a period.
Question 7. Which of the following sources is considered an active element? A) Resistor B) Battery C) Voltage-controlled voltage source (VCVS) D) Inductor Answer: C Explanation: A voltage-controlled voltage source (VCVS) is an active element because it can supply power to the circuit and depends on an external control voltage. Question 8. In a resistor, the voltage-current relationship in DC steady-state is described by: A) V = L × di/dt B) V = 1 / (jωC) × I C) V = R × I D) V = 1 / R × I Answer: C Explanation: Ohm's Law states V = R × I for resistors in DC steady-state.
Question 9. Which law states that the algebraic sum of voltages around any closed loop in a circuit equals zero? A) Ohm's Law B) Kirchhoff's Voltage Law (KVL) C) Kirchhoff's Current Law (KCL) D) Thevenin's Theorem Answer: B Explanation: Kirchhoff's Voltage Law (KVL) asserts that the sum of voltages around any closed loop is zero, reflecting energy conservation. Question 10. Which law states that the total current entering a junction equals the total current leaving? A) Ohm's Law B) Kirchhoff's Voltage Law C) Kirchhoff's Current Law (KCL) D) Thevenin's Theorem Answer: C Explanation: Kirchhoff's Current Law (KCL) states that the algebraic sum of currents at a junction is zero, ensuring charge conservation.
Question 13. When transforming a delta (Δ) network to a wye (Y) network, which of the following is true? A) The resistances are related by specific formulas involving products and sums of the original resistances. B) The transformation only applies to voltage sources. C) The transformation applies only to inductors. D) Delta to wye transformation simplifies only capacitor networks. Answer: A Explanation: Delta-Wye (Δ-Y) transformation involves formulas that relate resistances in the delta configuration to those in the wye configuration using products and sums. Question 14. In nodal analysis, what is the primary unknown variable? A) Branch currents B) Node voltages C) Loop currents D) Resistance values Answer: B
Explanation: Nodal analysis focuses on calculating the node voltages relative to a reference node by solving systems of equations. Question 15. Which of the following best describes a supernode? A) A combination of multiple resistors in series B) A node that contains multiple voltage sources C) A group of nodes connected by voltage sources or dependent sources, treated as a single node for analysis D) A node with zero voltage Answer: C Explanation: A supernode encompasses two or more nodes connected by voltage sources or dependent sources, simplifying circuit analysis. Question 16. Mesh analysis involves writing equations based on: A) Node voltages B) Loop currents C) Branch resistances D) Junction voltages Answer: B
Explanation: Superposition applies only to linear circuits with multiple independent sources; dependent sources are handled separately. Question 19. Thevenin's equivalent circuit consists of: A) An ideal current source in series with a resistor B) An ideal voltage source in parallel with a resistor C) A dependent source only D) Multiple resistors in series Answer: B Explanation: Thevenin's equivalent is modeled as a single voltage source in series with a resistor, simplifying complex circuits for analysis. Question 20. Norton's equivalent circuit consists of: A) An ideal current source in parallel with a resistor B) An ideal voltage source in series with a resistor C) A dependent current source only D) Multiple resistors in parallel Answer: A Explanation: Norton's equivalent is a current source in parallel with a resistor, representing the same behavior as the original network.
Question 21. The natural response of a first-order RC circuit is characterized by: A) Exponential decay or growth depending on initial conditions B) Sinusoidal oscillations only C) Constant voltage over time D) Linear increase in current Answer: A Explanation: First-order RC circuits exhibit exponential decay or rise in response to initial conditions, governed by time constants. Question 22. The time constant (τ) for an RC circuit is given by: A) τ = R × C B) τ = R / C C) τ = 1 / (R × C) D) τ = R + C Answer: A Explanation: The time constant τ = R × C determines how quickly the capacitor charges or discharges.
Question 25. The natural frequency (ω0) of a second-order RLC circuit is given by: A) ω0 = 1 / √(L C) B) ω0 = R / L C) ω0 = 1 / (L C) D) ω0 = √(L / C) Answer: A Explanation: The natural frequency ω0 = 1 / √(L C) determines the frequency of oscillations in an undamped RLC circuit. Question 26. In sinusoidal steady-state analysis, the phasor representation of a sinusoid involves: A) Amplitude and phase only B) Magnitude and phase angle only C) Frequency and time delay only D) Resistance and reactance only Answer: B Explanation: Phasors represent sinusoidal signals by their magnitude (amplitude) and phase angle, simplifying sinusoidal analysis.
Question 27. The impedance of a capacitor at angular frequency ω is: A) Z_C = jωL B) Z_C = 1 / (jωC) C) Z_C = R + jωL D) Z_C = R + 1 / (jωC) Answer: B Explanation: Capacitor impedance is Z_C = 1 / (jωC), reflecting its frequency- dependent opposition to current. Question 28. In a series RLC circuit at resonance, the impedance is: A) Purely resistive, Z = R B) Purely reactive, Z = jX_L - jX_C C) Zero D) Infinite Answer: A Explanation: At resonance, reactive components cancel (X_L = X_C), leaving the impedance purely resistive, Z = R. Question 29. The quality factor (Q) of a series RLC circuit is defined as: A) Q = ω0 L / R
D) Frequencies where the system response is zero Answer: C Explanation: Poles are roots of the denominator of H(s), indicating system resonances and stability characteristics. Question 32. In the Laplace domain, initial conditions are incorporated by: A) Zeroing all s terms B) Using initial condition terms in the Laplace transforms of circuit elements C) Ignoring initial conditions for transient analysis D) Only applying in steady-state analysis Answer: B Explanation: Initial conditions appear explicitly in Laplace transforms as terms added to the equations, allowing for complete transient analysis. Question 33. Two-port networks are characterized by: A) Voltage and current at two different points of a circuit B) Only their impedance C) The number of resistors connected D) Their frequency response only Answer: A
Explanation: Two-port networks relate the voltages and currents at two ports, enabling modular analysis of complex systems. Question 34. The Z-parameters of a two-port network are defined as: A) The open-circuit voltage ratios B) The input and output impedance parameters C) The impedance matrix relating port voltages and currents when other ports are open-circuited D) The current ratios when the ports are shorted Answer: C Explanation: Z-parameters relate port voltages to currents with other ports open, forming an impedance matrix. Question 35. The Y-parameters of a two-port network are derived by: A) Short-circuiting the ports and measuring currents B) Open-circuiting the ports and measuring voltages C) Applying voltage sources and measuring currents with open ports D) Measuring the impedance directly Answer: C
Question 38. A low-pass filter allows signals: A) Below a certain cutoff frequency to pass B) Above a certain cutoff frequency to pass C) Only at the resonant frequency D) Only DC signals Answer: A Explanation: Low-pass filters pass signals with frequencies below the cutoff frequency, attenuating higher frequencies. Question 39. The cutoff frequency of a first-order RC low-pass filter is given by: A) 1 / (2π R C) B) R / C C) 2π R C D) R × C Answer: A Explanation: The cutoff frequency (f_c) = 1 / (2π R C) defines the frequency at which the output drops to approximately 70.7% of the input.
Question 40. In a band-pass filter, the bandwidth is defined as: A) The difference between the upper and lower cutoff frequencies B) The sum of the cutoff frequencies C) The square root of the product of cutoff frequencies D) The reciprocal of the quality factor Q Answer: A Explanation: Bandwidth = f_high - f_low, representing the frequency range passed by the filter. Question 41. The complex power S in an AC circuit is expressed as: A) S = VI* (where I* is the complex conjugate of I) B) S = V / I C) S = V + I D) S = P + Q, where P is real power and Q reactive power Answer: D Explanation: Complex power S = P + jQ combines real power (P) and reactive power (Q), representing total power flow. Question 42. Power factor is defined as: A) The ratio of real power to apparent power
