Free Circuit Analysis MCQs with Answers

• A. Energy
• B. Time
• C. Power
• D. Charge

Explanation: A kilowatt-hour is a unit of energy because it equals power multiplied by time.

• A. zero
• B. infinite
• C. finite
• D. 100 ohms

Explanation: An ideal voltage source maintains constant terminal voltage regardless of load current, which requires zero internal resistance.

• A. current
• B. voltage
• C. power
• D. None of the above

Explanation: A capacitor cannot undergo an instantaneous change in voltage because its current is related by i = C dv/dt.

• A. current
• B. voltage
• C. power
• D. None of the above

Explanation: An inductor cannot undergo an instantaneous change in current because its voltage is related by v = L di/dt.

• A. Maximum
• B. Minimum
• C. Zero
• D. A finite value

Explanation: An ideal inductor stores energy in its magnetic field and returns it to the circuit, so its average power dissipation is zero.

• A. Resistor
• B. Bulb
• C. Both
• D. None of these.

Explanation: A resistor and an ordinary bulb are both passive elements because they consume or dissipate energy rather than generating or amplifying…

• A. 0.625 x 10^19
• B. 1.6 x 10^19
• C. 1.6 x 10^-19
• D. 0.625 x 10^-19

Explanation: Since 1 ampere equals 1 coulomb per second and one electron carries approximately 1.6 × 10^-19 C, the number of electrons per second is…

• A. area of the conductor.
• B. length of the conductor.
• C. type of material.
• D. none of these.

Explanation: Resistivity is an intrinsic property of a material, so it depends on the conductor's type of material and, under ordinary assumptions, its…

• A. R Ω
• B. 2R Ω
• C. 4R Ω
• D. 8R ΩCivil Engineering

Explanation: Using R = ρl/A, halving the diameter makes the cross-sectional area one-fourth, while doubling the length doubles the numerator.

• A. 10
• B. 60
• C. 600
• D. 1200

Explanation: Charge is Q = It, so Q = 10 A × 60 s = 600 C. The minute must first be converted into 60 seconds.

• A. product of the instantaneous current and rate of change of current.
• B. square of instantaneous current.
• C. square of the rate of change of current.
• D. Temperature of the inductor.

Explanation: For an inductor, v = L(di/dt), and instantaneous power is p = vi = Li(di/dt).

• A. product of its inductance and current through it.
• B. ratio of its inductance to the current through it.
• C. ratio of the current through it to its inductance.
• D. product of its inductance and rate of change of current through it.Electricity

Explanation: The inductor voltage follows v = L(di/dt), so it equals inductance multiplied by the rate of change of current.

• A. Newton
• B. Ampere-turn
• C. Weber
• D. Tesla

Explanation: Magnetic flux is measured in webers (Wb). A tesla measures flux density, while an ampere-turn represents magnetomotive force.

• A. Voltage source
• B. Current source
• C. Both
• D. None of these.

Explanation: Both voltage and current sources are active elements because each can deliver energy to an external circuit.