1000+ Electrical Circuits MCQ for GRE [Solved]

1. If two complex conjugates are addeda ___ components results.
A. In-phase
B. Quadrature
C. Complex
D. Outof-phase
Answer : A

2. For a linear circuita ___ voltage or current is used to calculate average power.
A. Rms
B. Peak
C. Average
D. Instantaneous
Answer : A

3. The voltage lags the current by cycle in a
A. Purely resistive circuit
B. Purely inductive circuit
C. Purely capacitive circuit
D. Circuit containing resistancea capacitance and inductance
Answer : C

4. A resistor wound with a wire doubled back on itself to reduce the inductance.
A. Bifilar resistor
B. Wire-wound resistor
C. Anti-inductive resistor
D. Bleeder resistor
Answer : A

5. For a series circuita the higher the quality factor
A. The greater the bandwidth
B. The narrower the passband
C. The broader the resonance curve
D. The wider the passband
Answer : B

6. In an ac circuit with a resistive branch and an inductive branch in parallela the
A. Voltage across the inductance leads the voltage across the resistance by 90°
B. Resistive branch current is 90° out of phase with the inductive branch current
C. Resistive and inductive branch currents have the same phase
D. Resistive and inductive branch currents are 180° outof-phase
Answer : B

7. Which of the following does not refer to electrical energy?
A. Volt-ampere
B. Joule
C. Watt-second
D. Volt-coulomb
Answer : A

8. In a multiple capacitora the plate area is
A. Increased
B. The same
C. Decreased
D. Variable
Answer : A

9. VL= VCin a series RLCcircuit when
A. The value of the impedance is minimum
B. The power factor is zero
C. The current leads the total voltage by 90�
D. The total voltage is zero
Answer : A

10. The presence of an electric current is made known by
A. Electric shock
B. Effects produced
C. Magnetic shock
D. Flashing
Answer : B

11. The distance between the capacitor plates increases two timesa then its capacitance
A. Increases two times
B. Increases four times
C. Decreases two times
D. Decreases four times
Answer : C

12. Permeability is otherwise known as
A. Magnetic conductivity
B. Magnetic susceptibility
C. Electric conductivity
D. Electric susceptibility
Answer : A

13. Rationalizing the denominator of a complex number means
A. Eliminating the j component in the denominator
B. Adding j component in the denominator
C. Eliminating the j component in the numerator
D. Adding j component in the numerator
Answer : A

14. Which is considered as the effect of a dielectric material?
A. Increasing capacitance
B. Decreasing capacitance
C. Reducing the working voltage
D. Increasing the distance between the plates
Answer : A

15. A coil of inductance L has an inductive reactance of XLin an ac circuit in which the effective current is I. The coil is made from a superconducting material. The rate at which power is dissipated in the coil is
A.
B. I2XL
C. IXL
D. IXL2
Answer : A

16. Which of the following does not affect resistance?
A. Resistivity
B. Cross-sectional area
C. Mass
D. Length
Answer : C

17. The arc across a switch when it open an RL circuit is a result of the
A. Large self-induced voltage across L
B. Long time constant
C. Low resistance of the open switch
D. Surge of resistance
Answer : A

18. Which of the following represents the energy stored in a cap
A. CV2/2
B. 2Q2/C
C. C2/V
D. CV
Answer : A

19. An inductance of 1 mH is
A. 0.001 H
B. 0.01 H
C. 0.0001 H
D. 0.10 H
Answer : A

20. The ___ of an alternating quantity is defined as the fractional part of a period or cycle through which the quantity has advanced from selected origin.
A. Phase
B. Frequency
C. Amplitude
D. Waveform
Answer : A

21. If a capacitor is rated for 200V dca what is its effective ac working voltage?
A. 50 V
B. 100 V
C. 200 V
D. 400 V
Answer : C

22. If two resistances of 9 and 6 are connected in parallela the total resistance is
A.
B.
C.
D.
Answer : D

23. An inductive circuit of resistance 16.5 and inductance of 0.14 H takes a current of 25 ?. if the frequency is 50 Hza find the supply voltage.
A. 1501 V
B. 1174V
C. 1877V
D. 991 V
Answer : B

24. How many degrees of phase represents one full cycle?
A.
B.
C.
D.
Answer : A

25. In a series RLCcircuit
A. The current lags VLby 90�
B. The current leads VLby 90�
C. XL leads Xcby 90�
D. Z = jXL at resonance
Answer : A

26. Which statement is true about a passive circuit?
A. A circuit with neither a source of current nor a source of potential difference
B. A circuit with a voltage source
C. A circuit with a current source
D. A circuit with only resistance as a load
Answer : A

27. For greater accuracya the value of phase angle should be determined from
A. Cos
B. Tan
C. Sin
D. Sec
Answer : B

28. A series-parallel combination of identical resistors will
A. Increase the power rating compared with one resistor alone
B. Increase the voltage rating compared with one resistor alone
C. Reduce the voltage rating compared with resistor alone
D. Result in an expensive circuit
Answer : A

29. Two capacitors of capacitance 9 F and 18 F in series will have a total capacitance of
A. 27 F
B. 162 F
C. 6 F
D. 180 F
Answer : C

30. What fusion of elements is without chemical action between them?
A. Mixture
B. Compound
C. Alloy
D. Ionization
Answer : C

31. Electric energy refers to
A. Volt divided by coulomb
B. Voltampere
C. Volt-coulomb
D. Watt divided by time
Answer : C

32. A trigger circuit consisting of a capacitor of 0.01 F is connected in series with a resistor. If the circuit requires 100 Vdcto operatea determine the value of the resistor when time constant is 0.009s.
A.
B. 900 k
C. 900 M
D. 900 G
Answer : B

33. Form its definitiona the unit of electric fielda is the N/C and equivalent unit of is the
A. V(m)2
B. V(m)
C. V/m2
D. V/m
Answer : D

34. Which of the following dielectric materials makes the lowest-capacitance capacitor?
A. Paper
B. Mica
C. Air
D. Electrolyte
Answer : C

35. It is impossible to change the voltage across a capacitor instantlya as this would produce ___ current.
A. Infinite
B. Zero
C. Low
D. High
Answer : A

36. The voltage cannot be exactly in phase with the current in a circuit that contains
A. Only capacitance
B. Only resistance
C. Inductance and capacitance
D. Inductancea capacitance and resistance
Answer : A

37. What can be used to estimate resonant frequency and to find reactance at any frequency for any value of capacitor or inductor?
A. Smith chart
B. Reactance chart
C. Impedance chart
D. Resonance chart
Answer : B

38. If a coil has a Q of 10a it means that
A. The energy stored in the magnetic field of the coil is 10 times the energy wasted in its resistance
B. The energy wasted in its resistance is 10 times the energy stored in the magnetic field of the coil
C. It is a low Q coil
D. It is a high Q coil
Answer : A

39. What is a closed path made of several branches of the network called?
A. Junction
B. Node
C. Terminal
D. Loop
Answer : D

40. What increases the resistance of wire at high frequencies?
A. Temperature
B. Voltage
C. Skin effect
D. Insulation
Answer : C

41. In a complex resistance-reactance planea XLis represented
A. By an axis opposite the R axis
B. By an axis perpendicular to the XC axis
C. By an axis opposite the XCaxis
D. By an axis parallel to the R axis
Answer : C

42. Two complex numbers or phasors are said to be conjugate if they
A. Differ only in the algebraic sign of their quadratic components
B. Differ only in the algebraic sign of their real components
C. Are equal in their real and quadrature components including alge
D. Are equal in their real components but differ in their quadrature components i ncluding algebraic signs.
Answer : A

43. A capacitor requires 12 C of charge to raise its potential of 3 V. What is the capacitance of the capacitor?
A. 36 F
B. 15 F
C. 0.25 F
D. 4 F
Answer : D

44. Metal tin becomes superconductor at approximately
A. 6 K
B. 3.7 K
C. 5 K
D. 4.7K
Answer : B

45. What is expected when two 20 k a 1 watt resistor in parallel are use instead of one 10 k a 1 watt?
A. Provides higher current
B. Provides less power
C. Provides more power
D. Provides wider tolerance
Answer : C

46. The wavelength of an alternating waveform depends upon the ___ of the variation.
A. Period
B. Number
C. Frequency
D. Amplitude
Answer : C

47. Which of the following is a common material used in wire-wound resistors?
A. Manganin
B. Carbon
C. Bronze
D. German silver wire
Answer : A

48. For maximum power transfera what is the relation between load resistance RL and internal resistance R of the voltage source?
A. RL= 2 r
B. RL= 1.5 r
C. RL= r
D. RL= 3 r
Answer : C

49. What capacitance exists not through design but simply because two conducting surfaces are relatively close to each other?
A. Surge
B. Stray
C. Natural
D. Normal
Answer : B

50. A linear circuit is one whose parameters
A. Change with change in voltage
B. Change with change in current
C. Do not change with voltage and current
D. Change with change in voltage and current
Answer : C