EEE MCQ — Circuit Theory & Network Analysis | ৫০টি প্রশ্ন ও উত্তর
BCS পরীক্ষায় Circuit Theory থেকে প্রতি বছর গুরুত্বপূর্ণ প্রশ্ন আসে। এই পোস্টে ৫০টি বাছাই করা MCQ দেওয়া হলো — উত্তরসহ। BCS Written, DESCO, BPDB, PGCB সহ সকল EEE চাকরির পরীক্ষার জন্য উপযোগী।
1. Ohm's Law states that current through a conductor is:
a) Inversely proportional to resistance, directly proportional to voltage
b) Directly proportional to both voltage and resistance
c) Independent of voltage
d) Inversely proportional to voltage
✅ Answer: a
2. The unit of electrical conductance is:
a) Ohm b) Farad c) Siemens d) Henry
✅ Answer: c
3. Kirchhoff's Current Law (KCL) is based on conservation of:
a) Energy b) Charge c) Power d) Momentum
✅ Answer: b
4. Kirchhoff's Voltage Law (KVL) states that the algebraic sum of all voltages around a closed loop is:
a) Equal to source voltage b) Maximum c) Zero d) Equal to load voltage
✅ Answer: c
5. In a series circuit, total resistance equals:
a) Less than the smallest resistance b) Equal to the largest resistance
c) Sum of all individual resistances d) Product of all resistances
✅ Answer: c
6. In a parallel circuit, total resistance is:
a) Greater than the largest resistance b) Less than the smallest resistance
c) Equal to sum of all resistances d) Equal to average of all resistances
✅ Answer: b
7. Thevenin's theorem replaces a complex network with:
a) A current source in parallel with a resistance
b) A voltage source in series with a resistance
c) A voltage source in parallel with a capacitor
d) A current source in series with an inductor
✅ Answer: b
8. Norton's theorem replaces a complex network with:
a) A voltage source in series with a resistance
b) A current source in parallel with a resistance
c) A voltage source in parallel with an inductor
d) A current source in series with a capacitor
✅ Answer: b
9. Superposition theorem is applicable to:
a) Non-linear circuits only b) Linear bilateral circuits only
c) All types of circuits d) Circuits with only resistors
✅ Answer: b
10. Maximum power transfer occurs when load resistance equals:
a) Zero b) Infinity c) Source resistance d) Twice the source resistance
✅ Answer: c
11. Time constant of an RC circuit is:
a) R/C b) RC c) R+C d) 1/RC
✅ Answer: b
12. Time constant of an RL circuit is:
a) RL b) R/L c) L/R d) 1/RL
✅ Answer: c
13. Inductive reactance (XL) is given by:
a) 1/(ωL) b) ωL c) ω/L d) L/ω
✅ Answer: b
14. Capacitive reactance (XC) is given by:
a) ωC b) 1/(ωC) c) ω/C d) C/ω
✅ Answer: b
15. At resonance in a series RLC circuit:
a) XL > XC b) XC > XL c) XL = XC d) Impedance is maximum
✅ Answer: c
16. Quality factor (Q) of a series resonant circuit is:
a) R/ωL b) ωL/R c) ωRC d) 1/ωRC
✅ Answer: b
17. Power factor is defined as:
a) cos θ — ratio of real power to apparent power b) sin θ
c) tan θ d) Ratio of reactive power to real power
✅ Answer: a
18. Reactive power is measured in:
a) Watts b) VA c) VAR d) kWh
✅ Answer: c
19. Apparent power is measured in:
a) Watts b) VA c) VAR d) kWh
✅ Answer: b
20. In a purely resistive AC circuit, current and voltage are:
a) 90° out of phase b) 180° out of phase c) In phase d) 45° out of phase
✅ Answer: c
21. In a purely inductive circuit, current lags voltage by:
a) 45° b) 90° c) 180° d) 0°
✅ Answer: b
22. In a purely capacitive circuit, current leads voltage by:
a) 180° b) 45° c) 90° d) 0°
✅ Answer: c
23. RMS value of a sinusoidal voltage with peak value Vm is:
a) Vm b) Vm/√2 c) Vm/2 d) √2 × Vm
✅ Answer: b
24. Average value of a full-wave rectified sinusoidal wave with peak Vm is:
a) 0.707 Vm b) 0.637 Vm c) 0.5 Vm d) Vm
✅ Answer: b
25. Form factor of a sinusoidal wave is:
a) 1.0 b) 1.11 c) 1.41 d) 0.707
✅ Answer: b
26. Energy stored in an inductor is:
a) LI b) ½LI² c) LI² d) ½LV²
✅ Answer: b
27. Energy stored in a capacitor is:
a) CV b) ½CV² c) CV² d) ½CI²
✅ Answer: b
28. In a three-phase balanced system, line voltage is related to phase voltage by:
a) VL = VP b) VL = √3 × VP c) VL = 3 × VP d) VL = VP/√3
✅ Answer: b
29. In a three-phase balanced delta connection, line current is related to phase current by:
a) IL = IP b) IL = IP/√3 c) IL = √3 × IP d) IL = 3 × IP
✅ Answer: c
30. Total power in a three-phase balanced circuit is:
a) P = VI cos θ b) P = √3 × VL × IL × cos θ
c) P = 3 × VL × IL × cos θ d) P = VL × IL
✅ Answer: b
31. Star (Y) to Delta (Δ): if all three star resistances are R, each delta resistance equals:
a) R/3 b) R c) 3R d) R²
✅ Answer: c
32. Node voltage method is based on:
a) KVL b) KCL c) Ohm's Law only d) Superposition theorem
✅ Answer: b
33. Mesh analysis is based on:
a) KCL b) KVL c) Norton's theorem d) Thevenin's theorem
✅ Answer: b
34. A network is bilateral if:
a) It contains only resistors b) It behaves the same for current in both directions
c) It has two terminals d) It has only one source
✅ Answer: b
35. The reciprocity theorem applies to:
a) Non-linear circuits b) Linear passive bilateral networks
c) Active networks only d) Networks with dependent sources
✅ Answer: b
36. Average power consumed by a pure inductor in AC circuit is:
a) Maximum b) Minimum c) Zero d) Equal to I²XL
✅ Answer: c
37. The bandwidth of a series RLC circuit is:
a) ω₀/Q b) Q/ω₀ c) ω₀ × Q d) R × L
✅ Answer: a
38. Laplace transform is used in circuit analysis to:
a) Convert differential equations to algebraic equations b) Measure power
c) Find resonant frequency d) Convert AC to DC
✅ Answer: a
39. Millman's theorem is used to find:
a) Current in a branch b) Voltage across parallel branches with different sources
c) Power in a circuit d) Thevenin's resistance
✅ Answer: b
40. Input impedance of an ideal voltage source is:
a) Infinite b) Zero c) Equal to load resistance d) 50 Ohm
✅ Answer: b
41. Input impedance of an ideal current source is:
a) Zero b) Equal to load c) Infinite d) 100 Ohm
✅ Answer: c
42. Tellegen's theorem states that the sum of power delivered by all branches in a network is:
a) Maximum b) Minimum c) Zero d) Equal to source power
✅ Answer: c
43. In AC circuit analysis, a phasor represents:
a) Instantaneous value of a sinusoidal quantity b) Peak value only
c) Magnitude and phase of a sinusoidal quantity d) Average value
✅ Answer: c
44. Two-wattmeter method measures power in:
a) Single-phase circuits b) DC circuits
c) Three-phase three-wire circuits d) Single-phase two-wire circuits
✅ Answer: c
45. A passive network contains:
a) Only dependent sources b) No energy sources
c) Independent voltage sources only d) Current sources only
✅ Answer: b
46. Dual of a voltage source is:
a) Resistance b) Current source c) Capacitor d) Inductor
✅ Answer: b
47. In resonance, the impedance of a series RLC circuit is:
a) Maximum b) Zero c) Purely resistive (minimum) d) Purely reactive
✅ Answer: c
48. The two-port network ABCD parameters are most useful for:
a) Amplifier circuits b) Cascaded networks and transmission lines
c) Resonant circuits d) Filter design only
✅ Answer: b
49. If a 10Ω and 20Ω resistor are connected in parallel, the equivalent resistance is:
a) 30Ω b) 15Ω c) 6.67Ω d) 5Ω
✅ Answer: c (10×20)/(10+20) = 200/30 = 6.67Ω
50. A 100V source with internal resistance 5Ω delivers maximum power to a load of:
a) 10Ω b) 5Ω c) 2.5Ω d) 20Ω
✅ Answer: b (Maximum power transfer: RL = RS = 5Ω)
গুরুত্বপূর্ণ সূত্র সংক্ষেপ
| বিষয় | সূত্র |
|---|---|
| Time constant RC | τ = RC |
| Time constant RL | τ = L/R |
| Resonant frequency | f₀ = 1/(2π√LC) |
| Quality Factor | Q = ωL/R |
| RMS Voltage | Vrms = Vm/√2 |
| Three-phase power | P = √3 × VL × IL × cosθ |
| Max power transfer | RL = RTh |
পরবর্তী পোস্ট: Electrical Machines MCQ — ৫০টি প্রশ্ন ও উত্তর
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