At a junction, 2 A and 3 A enter while 1 A leaves. What current must also leave?
A 5 A
B 3 A
C 1 A
D 4 A
Answer: D. 4 A. KCL balances currents: 2 + 3 = 1 + I, so I = 4 A.
What quantity remains fixed for an ideal independent voltage source?
A Branch current
B Delivered power
C Internal drop
D Terminal voltage
Answer: D. Terminal voltage. An ideal independent voltage source maintains its specified terminal voltage.
Combining 4 Ω and 6 Ω resistors in series gives what?
A 1.2 Ω
B 2 Ω
C 24 Ω
D 10 Ω
Answer: D. 10 Ω. Series resistances add: 4 + 6 = 10 Ω.
Two equal 6 Ω resistors in parallel have what equivalent?
A 6 Ω
B 36 Ω
C 12 Ω
D 3 Ω
Answer: D. 3 Ω. Two equal parallel resistors have half the resistance of one: 3 Ω.
Around any closed electrical loop, the algebraic voltage sum equals what?
A Source voltage
B Zero volts
C Load current
D Infinite voltage
Answer: B. Zero volts. Kirchhoff’s voltage law makes the signed voltage changes sum to zero.
Which SI unit measures conductance?
A Henry
B Siemens
C Farad
D Weber
Answer: B. Siemens. Conductance is measured in siemens, the reciprocal of the ohm.
What current flows through 4 kΩ at 12 V?
A 3 mA
B 4 mA
C 0.33 mA
D 48 mA
Answer: A. 3 mA. Ohm’s law gives 12 V/4 kΩ = 3 mA.
Which ideal component stores energy in an electric field?
A Capacitor
B Resistor
C Transformer
D Inductor
Answer: A. Capacitor. A capacitor stores energy in its electric field.
Magnetic-field energy is stored by which ideal element?
A Source
B Resistor
C Capacitor
D Inductor
Answer: D. Inductor. An inductor stores energy in the magnetic field produced by its current.
How is a connection point shared by branches named?
A Port
B Loop
C Node
D Mesh
Answer: C. Node. A node is a connection point shared by element terminals.
What current flows through an ideal open branch?
A 0 A
B 1 A
C Infinite current
D Load-dependent current
Answer: A. 0 A. An open circuit interrupts the path, so its ideal current is zero.
What voltage appears across an ideal short circuit?
A 0 V
B Source voltage
C Infinite voltage
D Undefined voltage
Answer: A. 0 V. An ideal short has zero resistance and zero terminal voltage.
Which quantity is equal through series components?
A Voltage
B Current
C Power
D Resistance
Answer: B. Current. Elements in one series path carry the same current.
What does an ideal independent current source hold constant?
A Resistance
B Current
C Voltage
D Power
Answer: B. Current. An ideal current source fixes its specified current.
The relation V = IR is known by what name?
A Lenz’s law
B Faraday’s law
C Ohm’s law
D Kirchhoff’s law
Answer: C. Ohm’s law. Ohm’s law relates voltage, current, and resistance for an ohmic element.
Across a 10 Ω resistor carrying 2 A, what voltage appears?
A 20 V
B 5 V
C 10 V
D 40 V
Answer: A. 20 V. Using V = IR gives 2 A × 10 Ω = 20 V.
Charge of 6 C passes in 2 s. What current flows?
A 1 A
B 12 A
C 3 A
D 2 A
Answer: C. 3 A. Current is charge per time: 6 C/2 s = 3 A.
With a 2 F capacitor at 3 V, how much charge is stored?
A 1.5 C
B 9 C
C 6 C
D 5 C
Answer: C. 6 C. Q = CV = 2 F × 3 V = 6 C.
The ideal internal resistance of a voltage source is what?
A 1 Ω
B Load-dependent
C 0 Ω
D Infinite
Answer: C. 0 Ω. An ideal voltage source has zero internal resistance.
The ideal internal resistance of a current source is what?
A 1 Ω
B Load-dependent
C 0 Ω
D Infinite
Answer: D. Infinite. An ideal current source has infinite internal resistance.
Capacitance is measured in which SI unit?
A Siemens
B Farad
C Henry
D Coulomb
Answer: B. Farad. The SI unit of capacitance is the farad.
Inductance is measured in which SI unit?
A Henry
B Ohm
C Weber
D Farad
Answer: A. Henry. The SI unit of inductance is the henry.
If an assumed current direction is wrong, its calculated sign becomes what?
A Negative
B Imaginary
C Positive
D Zero
Answer: A. Negative. A negative result means actual current flows opposite the assumed arrow.
Under passive sign convention, positive power means what?
A Reactive power
B Absorbed power
C Zero power
D Delivered power
Answer: B. Absorbed power. With current entering the positive-voltage terminal, positive vi denotes absorbed power.
Which ideal component converts electrical energy into heat?
A Source
B Capacitor
C Resistor
D Inductor
Answer: C. Resistor. An ideal resistor dissipates electrical energy as heat.