DC Circuits and Network Theorems MCQs 2026
111 questions with detailed answers · 36 from past papers · 12 quiz batches available
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- Q1 Past Paper · PPSC/FPSC/CSS easy
Kirchhoff Current Law at a node states that
💡 Explanation:KCL follows from conservation of charge.
- Q2 hard
Wheatstone bridge P=100, Q=200, R=150 ohm; unknown S at balance is
💡 Explanation:100/200 = 150/S → S = 300 ohm.
- Q3 Past Paper · PPSC/FPSC/CSS easy
Kirchhoff Voltage Law around a closed loop states that
💡 Explanation:KVL follows from conservation of energy.
- Q4 Past Paper · PPSC/FPSC/CSS easy
Power dissipated in a resistor carrying current I is
💡 Explanation:P = I²R = VI = V²/R for a resistor.
- Q5 Past Paper · PPSC/FPSC/CSS easy
Conductance G of resistance R equals
💡 Explanation:G = 1/R in siemens.
- Q6 Past Paper · PPSC/FPSC/CSS easy
In a series circuit the current through each element is
💡 Explanation:Single path: same current everywhere.
- Q7 Past Paper · PPSC/FPSC/CSS easy
In a parallel circuit the voltage across each branch is
💡 Explanation:Parallel branches share the same potential.
- Q8 Past Paper · PPSC/FPSC/CSS medium
A 100 W, 250 V lamp has hot resistance approximately
💡 Explanation:R = V²/P = 62500/100 = 625 ohm.
- Q9 Past Paper · PPSC/FPSC/CSS medium
A 220 V, 1000 W heater resistance is approximately
💡 Explanation:R = V²/P = 48400/1000 = 48.4 ohm.
- Q10 easy
Balanced Wheatstone bridge galvanometer shows
💡 Explanation:Zero current in galvanometer at balance.
- Q11 easy
Energy in a pure resistor is
💡 Explanation:Resistors dissipate; they do not store energy.
- Q12 easy
A practical ammeter should have
💡 Explanation:Low R minimizes loading error.
- Q13 easy
Thevenin equivalent of a linear network is
💡 Explanation:Thevenin: Vth + series Rth.
- Q14 easy
Norton equivalent of a linear network is
💡 Explanation:Norton: In || Rn.
- Q15 medium
Thevenin voltage Vth is measured as
💡 Explanation:Vth = Voc at terminals.
- Q16 medium
Thevenin resistance Rth is found by
💡 Explanation:Zero sources; compute R at terminals.
- Q17 medium
Norton current In equals
💡 Explanation:In = Isc at terminals.
- Q18 medium
For maximum power transfer to load, R_L should equal
💡 Explanation:Max power when R_L = Rth.
- Q19 hard
Maximum power when Vth=20 V and Rth=5 ohm with matched load is
💡 Explanation:Pmax = V²/(4R) = 400/20 = 20 W.
- Q20 hard
At maximum power transfer the efficiency is
💡 Explanation:Half power in Rth, half in R_L.
- Q21 medium
Superposition applies to
💡 Explanation:Response = sum of individual source responses.
- Q22 medium
When using superposition, other voltage sources are replaced by
💡 Explanation:Ideal voltage sources → shorts.
- Q23 medium
When using superposition, other current sources are replaced by
💡 Explanation:Ideal current sources → opens.
- Q24 medium
Superposition cannot find directly
💡 Explanation:Power is nonlinear in current.
- Q25 medium
If Vth=12 V and Rth=4 ohm, Norton current is
💡 Explanation:In = Vth/Rth = 3 A.
- Q26 medium
Source transformation: V in series with R becomes current source
💡 Explanation:I = V/R with same R.
- Q27 hard
Reciprocity theorem applies to
💡 Explanation:Interchange excitation and response in linear bilateral nets.
- Q28 medium
Mesh analysis uses
💡 Explanation:Mesh currents + KVL per loop.
- Q29 medium
Nodal analysis uses
💡 Explanation:Node voltages + KCL.
- Q30 medium
Independent nodal equations for n nodes number
💡 Explanation:One reference node at 0 V.
- Q31 hard
Independent mesh equations for b branches and n nodes in planar net
💡 Explanation:Independent loops = b - n + 1.
- Q32 medium
A Wheatstone bridge is balanced when
💡 Explanation:Balance: P/Q = R/S.
- Q33 hard
Delta to wye: each wye resistor equals
💡 Explanation:Standard delta-wye transform.
- Q34 hard
Three 6 ohm delta resistors convert to each wye arm of
💡 Explanation:Ry = 6×6/18 = 2 ohm.
- Q35 medium
Three 9 ohm delta to wye gives each arm
💡 Explanation:Ry = 81/27 = 3 ohm.
- Q36 medium
Voltage divider: R1 and R2 in series across V, voltage on R2 is
💡 Explanation:Series divider formula.
- Q37 medium
Current divider: R1 parallel R2, total I, current in R1 is
💡 Explanation:Current splits inversely with R.
- Q38 hard
Millman theorem combines
💡 Explanation:Single equivalent for parallel branches.
- Q39 hard
Tellegen theorem relates to
💡 Explanation:Topological power relation.
- Q40 hard
Star-delta: each delta resistor from wye uses
💡 Explanation:Standard Y-delta conversion.
- Q41 easy
A 6 V source drives 2 ohm load. Load current is
💡 Explanation:I = V/R = 3 A.
- Q42 easy
A 10 V source drives 5 ohm load. Load current is
💡 Explanation:I = V/R = 2 A.
- Q43 easy
A 24 V source drives 8 ohm load. Load current is
💡 Explanation:I = V/R = 3 A.
- Q44 easy
A 30 V source drives 10 ohm load. Load current is
💡 Explanation:I = V/R = 3 A.
- Q45 easy
A 15 V source drives 5 ohm load. Load current is
💡 Explanation:I = V/R = 3 A.
- Q46 easy
A 20 V source drives 4 ohm load. Load current is
💡 Explanation:I = V/R = 5 A.
- Q47 easy
A 12 V source drives 6 ohm load. Load current is
💡 Explanation:I = V/R = 2 A.
- Q48 easy
A 18 V source drives 6 ohm load. Load current is
💡 Explanation:I = V/R = 3 A.
- Q49 easy
A 9 V source drives 3 ohm load. Load current is
💡 Explanation:I = V/R = 3 A.
- Q50 easy
A 16 V source drives 4 ohm load. Load current is
💡 Explanation:I = V/R = 4 A.
- Q51 medium
4 ohm, 6 ohm, 10 ohm in series across 20 V gives current
💡 Explanation:R = 20 ohm; I = 20/20 = 1 A.
- Q52 medium
5 ohm, 5 ohm, 10 ohm in series across 20 V gives current
💡 Explanation:R = 20 ohm; I = 20/20 = 1 A.
- Q53 medium
1 ohm, 2 ohm, 7 ohm in series across 10 V gives current
💡 Explanation:R = 10 ohm; I = 10/10 = 1 A.
- Q54 Past Paper · PPSC/FPSC/CSS easy
A 20 ohm resistor carries 3 A. The voltage across it is
💡 Explanation:V = IR = 20 × 3 = 60 V.
- Q55 medium
3 ohm, 3 ohm, 4 ohm in series across 10 V gives current
💡 Explanation:R = 10 ohm; I = 10/10 = 1 A.
- Q56 medium
Resistors 12, 6, 4 ohm in parallel give
💡 Explanation:1/Req = 1/12+1/6+1/4; Req = 2 ohm.
- Q57 medium
Resistors 10, 15, 30 ohm in parallel give
💡 Explanation:1/Req = 1/10+1/15+1/30; Req = 5 ohm.
- Q58 medium
Resistors 8, 8, 8 ohm in parallel give
💡 Explanation:1/Req = 1/8+1/8+1/8; Req = 8/3 ohm.
- Q59 medium
Resistors 20, 10, 20 ohm in parallel give
💡 Explanation:1/Req = 1/20+1/10+1/20; Req = 5 ohm.
- Q60 medium
Resistors 6, 3, 2 ohm in parallel give
💡 Explanation:1/Req = 1/6+1/3+1/2; Req = 1 ohm.
- Q61 Past Paper · PPSC/FPSC/CSS easy
A 12 ohm resistor carries 5 A. The voltage across it is
💡 Explanation:V = IR = 12 × 5 = 60 V.
- Q62 Past Paper · PPSC/FPSC/CSS easy
Two resistors 10 ohm and 40 ohm in parallel have equivalent resistance of
💡 Explanation:Parallel: 1/R = 1/10+1/40; R = 8 ohm.
- Q63 Past Paper · PPSC/FPSC/CSS easy
Two resistors 20 ohm and 5 ohm in parallel have equivalent resistance of
💡 Explanation:Parallel: 1/R = 1/20+1/5; R = 4 ohm.
- Q64 Past Paper · PPSC/FPSC/CSS easy
Two resistors 6 ohm and 3 ohm in parallel have equivalent resistance of
💡 Explanation:Parallel: 1/R = 1/6+1/3; R = 2 ohm.
- Q65 Past Paper · PPSC/FPSC/CSS easy
Two resistors 12 ohm and 4 ohm in parallel have equivalent resistance of
💡 Explanation:Parallel: 1/R = 1/12+1/4; R = 3 ohm.
- Q66 Past Paper · PPSC/FPSC/CSS easy
Resistors 4 ohm, 8 ohm connected in series have equivalent resistance of
💡 Explanation:Series: R = 4+8 = 12 ohm.
- Q67 Past Paper · PPSC/FPSC/CSS easy
A 15 ohm resistor carries 4 A. The voltage across it is
💡 Explanation:V = IR = 15 × 4 = 60 V.
- Q68 Past Paper · PPSC/FPSC/CSS easy
A 50 ohm resistor carries 0.5 A. The voltage across it is
💡 Explanation:V = IR = 50 × 0.5 = 25 V.
- Q69 Past Paper · PPSC/FPSC/CSS easy
A 100 ohm resistor carries 0.2 A. The voltage across it is
💡 Explanation:V = IR = 100 × 0.2 = 20 V.
- Q70 Past Paper · PPSC/FPSC/CSS easy
A 25 ohm resistor carries 2 A. The voltage across it is
💡 Explanation:V = IR = 25 × 2 = 50 V.
- Q71 Past Paper · PPSC/FPSC/CSS easy
Two resistors 8 ohm and 8 ohm in parallel have equivalent resistance of
💡 Explanation:Parallel: 1/R = 1/8+1/8; R = 4 ohm.
- Q72 Past Paper · PPSC/FPSC/CSS easy
Resistors 5 ohm, 7 ohm, 3 ohm connected in series have equivalent resistance of
💡 Explanation:Series: R = 5+7+3 = 15 ohm.
- Q73 Past Paper · PPSC/FPSC/CSS easy
Resistors 2 ohm, 2 ohm, 2 ohm connected in series have equivalent resistance of
💡 Explanation:Series: R = 2+2+2 = 6 ohm.
- Q74 easy
Balanced Wheatstone bridge galvanometer shows
💡 Explanation:Zero current in galvanometer at balance.
- Q75 hard
Wheatstone bridge P=100, Q=200, R=150 ohm; unknown S at balance is
💡 Explanation:100/200 = 150/S → S = 300 ohm.
- Q76 Past Paper · PPSC/FPSC/CSS easy
A 10 ohm resistor carries 2 A. The voltage across it is
💡 Explanation:V = IR = 10 × 2 = 20 V.
- Q77 Past Paper · PPSC/FPSC/CSS easy
A 5 ohm resistor carries 4 A. The voltage across it is
💡 Explanation:V = IR = 5 × 4 = 20 V.
- Q78 Past Paper · PPSC/FPSC/CSS easy
Kirchhoff Current Law at a node states that
💡 Explanation:KCL follows from conservation of charge.
- Q79 Past Paper · PPSC/FPSC/CSS easy
Kirchhoff Voltage Law around a closed loop states that
💡 Explanation:KVL follows from conservation of energy.
- Q80 Past Paper · PPSC/FPSC/CSS easy
Power dissipated in a resistor carrying current I is
💡 Explanation:P = I²R = VI = V²/R for a resistor.
- Q81 Past Paper · PPSC/FPSC/CSS easy
Conductance G of resistance R equals
💡 Explanation:G = 1/R in siemens.
- Q82 Past Paper · PPSC/FPSC/CSS easy
In a series circuit the current through each element is
💡 Explanation:Single path: same current everywhere.
- Q83 Past Paper · PPSC/FPSC/CSS easy
In a parallel circuit the voltage across each branch is
💡 Explanation:Parallel branches share the same potential.
- Q84 Past Paper · PPSC/FPSC/CSS medium
A 100 W, 250 V lamp has hot resistance approximately
💡 Explanation:R = V²/P = 62500/100 = 625 ohm.
- Q85 Past Paper · PPSC/FPSC/CSS medium
A 220 V, 1000 W heater resistance is approximately
💡 Explanation:R = V²/P = 48400/1000 = 48.4 ohm.
- Q86 easy
Energy in a pure resistor is
💡 Explanation:Resistors dissipate; they do not store energy.
- Q87 easy
A practical ammeter should have
💡 Explanation:Low R minimizes loading error.
- Q88 easy
Thevenin equivalent of a linear network is
💡 Explanation:Thevenin: Vth + series Rth.
- Q89 easy
Norton equivalent of a linear network is
💡 Explanation:Norton: In || Rn.
- Q90 medium
Thevenin voltage Vth is measured as
💡 Explanation:Vth = Voc at terminals.
- Q91 medium
Thevenin resistance Rth is found by
💡 Explanation:Zero sources; compute R at terminals.
- Q92 medium
Norton current In equals
💡 Explanation:In = Isc at terminals.
- Q93 medium
For maximum power transfer to load, R_L should equal
💡 Explanation:Max power when R_L = Rth.
- Q94 hard
Maximum power when Vth=20 V and Rth=5 ohm with matched load is
💡 Explanation:Pmax = V²/(4R) = 400/20 = 20 W.
- Q95 hard
At maximum power transfer the efficiency is
💡 Explanation:Half power in Rth, half in R_L.
- Q96 medium
Superposition applies to
💡 Explanation:Response = sum of individual source responses.
- Q97 medium
When using superposition, other voltage sources are replaced by
💡 Explanation:Ideal voltage sources → shorts.
- Q98 medium
When using superposition, other current sources are replaced by
💡 Explanation:Ideal current sources → opens.
- Q99 medium
Superposition cannot find directly
💡 Explanation:Power is nonlinear in current.
- Q100 medium
If Vth=12 V and Rth=4 ohm, Norton current is
💡 Explanation:In = Vth/Rth = 3 A.
- Q101 medium
Source transformation: V in series with R becomes current source
💡 Explanation:I = V/R with same R.
- Q102 hard
Reciprocity theorem applies to
💡 Explanation:Interchange excitation and response in linear bilateral nets.
- Q103 medium
Mesh analysis uses
💡 Explanation:Mesh currents + KVL per loop.
- Q104 medium
Nodal analysis uses
💡 Explanation:Node voltages + KCL.
- Q105 medium
Independent nodal equations for n nodes number
💡 Explanation:One reference node at 0 V.
- Q106 hard
Independent mesh equations for b branches and n nodes in planar net
💡 Explanation:Independent loops = b - n + 1.
- Q107 medium
A Wheatstone bridge is balanced when
💡 Explanation:Balance: P/Q = R/S.
- Q108 Past Paper · PPSC/FPSC/CSS easy
A 4 ohm resistor carries 7 A. The voltage across it is
💡 Explanation:V = IR = 4 × 7 = 28 V.
- Q109 Past Paper · PPSC/FPSC/CSS easy
Resistors 10 ohm, 15 ohm connected in series have equivalent resistance of
💡 Explanation:Series: R = 10+15 = 25 ohm.
- Q110 Past Paper · PPSC/FPSC/CSS easy
Resistors 6 ohm, 3 ohm connected in series have equivalent resistance of
💡 Explanation:Series: R = 6+3 = 9 ohm.
- Q111 Past Paper · PPSC/FPSC/CSS easy
A 8 ohm resistor carries 2.5 A. The voltage across it is
💡 Explanation:V = IR = 8 × 2.5 = 20 V.