Between nodes at 6 V and 2 V, a 2 Ω resistor carries how much current from the higher potential?
A 2 A
B 1 A
C 3 A
D 4 A
Answer: A. 2 A. The voltage difference is 4 V, so current is 4/2 = 2 A.
At a junction, 3 A enters and 1 A leaves. How much more current must leave?
A 1 A
B 3 A
C 4 A
D 2 A
Answer: D. 2 A. KCL requires total outgoing current to equal the 3 A entering.
For a node at V volts linked to ground by R ohms, what is the outward current?
A R/V
B V/R
C VR
D V+R
Answer: B. V/R. Ohm’s law gives the current from the node to zero volts as V/R.
A voltage source joins a node directly to ground. What does it provide?
A Unknown mesh current
B Open-circuit resistance
C Known node voltage
D Parallel conductance
Answer: C. Known node voltage. Its polarity and magnitude set the node voltage relative to ground.
A floating source has its positive terminal at node a and negative at b. Which voltage constraint follows?
A Va equals Vb always
B Va−Vb = source voltage
C Va plus Vb equals zero
D Both nodes equal ground
Answer: B. Va−Vb = source voltage. The source imposes a specified voltage difference between its terminals.
A branch belongs to only one mesh. Its current equals what?
A Zero current
B Sum of all meshes
C That mesh current
D Norton current
Answer: C. That mesh current. Only that mesh current traverses the branch.
A current source lies only on the outer edge of one mesh. What is known?
A Every node voltage
B That mesh current
C Total circuit power
D Thévenin voltage
Answer: B. That mesh current. Its value and direction determine that mesh current directly.
Two clockwise meshes share a 4 Ω resistor. Mesh 1 sees which drop?
A 4(I1+I2) V
B 4(I1−I2) V
C I1/4 V
D 4I2 V
Answer: B. 4(I1−I2) V. The shared-branch current in mesh 1’s direction is I1 minus I2.
Where does the KVL path go for a supermesh?
A Around its outer boundary
B Through the current source
C Only around one resistor
D Across the reference node
Answer: A. Around its outer boundary. The outer perimeter bypasses the current-source branch.
After converting a practical voltage source to Norton form, its series resistance goes where?
A In series with current source
B Across an ideal short
C Parallel to current source
D Outside the network
Answer: C. Parallel to current source. Source transformation retains the resistance value but places it parallel to the current source.
Given Norton current In and resistance Rn, what is the Thévenin voltage?
A In times Rn
B In divided by Rn
C Rn divided by In
D In plus Rn
Answer: A. In times Rn. The open-circuit voltage of the Norton form is In × Rn.
A 5 A Norton source has 2 Ω in parallel. Its open-circuit voltage is what?
A 2.5 V
B 5 V
C 10 V
D 20 V
Answer: C. 10 V. With the terminals open, 5 A through 2 Ω gives 10 V.
A 9 V Thévenin source has 3 Ω series resistance. Its short-circuit current is what?
A 3 A
B 0 A
C 6 A
D 27 A
Answer: A. 3 A. The short-circuit current is 9/3 = 3 A.
When the load is removed for an open-circuit test, its branch current is what?
A Infinite
B Rated current
C Zero
D Source current
Answer: C. Zero. The removed load branch has no conducting path.
What voltage exists across ideal shorted output terminals?
A Source voltage always
B Infinite volts
C Zero volts
D One volt
Answer: C. Zero volts. An ideal short has zero voltage across its terminals.
For one superposition calculation, which independent source remains active?
A All independent sources
B No independent source
C Only dependent sources
D Selected source
Answer: D. Selected source. Keep the selected independent source while setting other independent sources to zero.
Why are separate source powers generally not added in superposition?
A Power is nonlinear
B Current is nonlinear
C KCL fails
D Resistance disappears
Answer: A. Power is nonlinear. Power depends on products or squares of circuit responses.
Three branches meet at a node. How many independent KCL equations exist for a two-node connected network?
A Two
B Three
C Zero
D One
Answer: D. One. With one reference node, the other node provides one independent KCL equation.
Two points are joined by an ideal wire. How do their potentials compare?
A Always opposite
B Differ by one volt
C Cannot be related
D Equal
Answer: D. Equal. An ideal wire has zero voltage drop along it.
Which quantity can be found from nonzero open-circuit voltage divided by short-circuit current?
A Total network power
B Port resistance
C Mesh count
D Node count
Answer: B. Port resistance. For a linear resistive two-terminal network, Rth = Voc/Isc.
A network section is replaced by its equivalent. What external element can stay connected?
A Original load
B Only internal nodes
C Removed sources
D Ground electrode only
Answer: A. Original load. The equivalent is defined to give the same terminal behavior for the load.
A 4 Ω and a 12 Ω resistor are parallel. What is their total conductance?
A 1/16 S
B 1/3 S
C 3 S
D 16 S
Answer: B. 1/3 S. Add conductances: 1/4 + 1/12 = 1/3 siemens.
Which SI unit expresses conductance?
A Ohm
B Henry
C Weber
D Siemens
Answer: D. Siemens. Conductance has the SI unit siemens.
When a resistive Wheatstone bridge is balanced, what flows in its cross branch?
A Zero current
B Source current
C Infinite current
D Equal source voltage
Answer: A. Zero current. The bridge midpoint potentials are equal, so the cross branch has no voltage difference.
For connected terminals of a network made only of finite positive resistors, driving-point resistance is what?
A Negative
B Imaginary
C Always zero
D Positive
Answer: D. Positive. A passive network of finite positive resistors has positive equivalent resistance at connected terminals.