Free Circuit Analysis MCQs with Answers

• A. the highest resistance has the most of the current through it
• B. the lowest resistance has the highest voltage drop
• C. the lowest resistance has the highest current
• D. the highest resistance has the highest voltage drop

Explanation: Current is identical through all components of a series circuit, so the current is not highest in the lowest-resistance element.

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

Explanation: An ampere-second is coulomb because current is charge flow per unit time, so charge equals current multiplied by time.

• A. Elements have individual currents
• B. Currents are additive
• C. Voltages are additive
• D. Power are additive

Explanation: Power is additive in both series and parallel circuits because total power equals the algebraic sum of the powers absorbed or supplied by…

• A. two in parallel
• B. two in parallel and one in series
• C. three in parallel
• D. three in series

Explanation: Two 1000-ohm resistors in parallel give 500 ohms; adding a third 1000-ohm resistor in series gives 1500 ohms.

• A. Manganin
• B. Porcelain
• C. Carbon
• D. Copper

Explanation: Manganin is an alloy selected for precision resistors because its resistance changes very little with temperature.

• A. 100 Ω
• B. 200 Ω
• C. 300 Ω
• D. 400 Ω

Explanation: Four identical wires in parallel have an equivalent resistance of R/4=25 ohms, so each wire is 100 ohms.

• A. 18 Q
• B. 36 Q
• C. 48 Q
• D. 64 Q

Explanation: For two parallel resistors, 1/12=1/18+1/R. Hence 1/R=1/36 and the other branch resistance is 36 ohms.

• A. 400 Q
• B. 600 Q
• C. 800 Q
• D. 1000 Q

Explanation: Using Ohm’s law, R=V/I=240/0.3=800 ohms. The 300 mA value must first be converted to 0.3 A.

• A. 33 V
• B. 66 v
• C. 80 V
• D. 132 V

Explanation: Ohm’s law gives V = IR = 2 × 33 = 66 V. The voltage is therefore proportional to both the resistance and the current.

• A. 1.2 x 10~8 Q-m
• B. 1.4 x 10~8 Q-m
• C. 1.6 x 10″"8 Q-m
• D. 1.8 x 10″8 Q-m

Explanation: Using ρ = RA/L and A = πd²/4, the cross-sectional area is about 1.52 × 10⁻⁷ m², giving ρ ≈ 1.6 × 10⁻⁸ Ω·m.

• A. increases
• B. decreases
• C. first increases and then decreases
• D. remains constant

Explanation: Pure metals have a positive temperature coefficient of resistance, so increased temperature causes greater atomic vibration and higher…

• A. length
• B. area of cross-section
• C. temperature
• D. resistivity

Explanation: From R = ρL/A, resistance decreases when the cross-sectional area A increases, so it varies inversely as area.

• A. resistance
• B. inductance
• C. reluctance
• D. capacitance

Explanation: Conductance is the ease with which current flows and is defined as the reciprocal of resistance: G = 1/R. Its unit is the siemens.

• A. resistance
• B. reluctance
• C. conductance
• D. inductance

Explanation: Conductance describes how readily a conductor allows current to pass, and is mathematically the reciprocal of resistance.

• A. resistance
• B. power
• C. voltage
• D. energy

Explanation: Electric pressure is the force that drives charge through a circuit, and it is measured as voltage or potential difference.

• A. Is equal to the source resistance
• B. Greater than the source resistance
• C. Smaller than the source resistance
• D. None of these

Explanation: Maximum power transfer occurs when the input resistance of the transmission line equals the source resistance, assuming purely resistive…

• A. Decrease with frequency
• B. Remains same with change in frequency
• C. Increase with frequency
• D. Either A. or B.

Explanation: The electrical length is βl, where β is proportional to frequency for a given transmission medium and physical length.

• A. Phase current
• B. Three times the phase current
• C. Three times the line current
• D. Zero at all times

Explanation: With no neutral connection, the star point has no path for current to enter or leave, so Kirchhoff’s current law requires the…

• A. Force
• B. Charge
• C. Current
• D. Power

Explanation: The watt is the SI unit of power, representing the rate of energy transfer.

• A. Permeability
• B. Moment of a magnet
• C. Magnetic susceptibility
• D. Permittivity

Explanation: Magnetic susceptibility is dimensionless because it is the ratio of magnetization to magnetizing field.