In this article, we shared the top 300 electrical circuits objective questions and answers for instrumentation, electrical, and electronics engineering students.
Electrical Circuits Questions
The below list provides all the multiple-choice questions (MCQ) related to electrical circuits.
Answers are available at the bottom of the article.
1. Which statement is true?
| A) | A series resonant circuit is of high impedance |
| B) | A parallel resonant circuit is of low impedance |
| C) | A parallel resonant circuit is inductive if it operates at a frequency higher than the resonant frequency |
| D) | A series resonant circuit is inductive if it operates at a frequency higher than the resonant frequency |
2. The admittance of a parallel RLC circuit is found to be the ___ sum of conductance and susceptances.
| A) | Phasor |
| B) | Arithmetic |
| C) | Vector |
| D) | Algebraic |
3. Which component opposes voltage change?
| A) | Capacitor |
| B) | Transistor |
| C) | Resistor |
| D) | Inductor |
4. Another term for a superconductor.
| A) | Ultraconductor |
| B) | Cryogenic conductor |
| C) | Cryotron |
| D) | Generic conductor |
5. In calculating maximum instantaneous power ____ voltage or current is used.
| A) | Peak |
| B) | RMS |
| C) | Instantaneous |
| D) | Average |
6. What is a closed path made of several branches of the network called?
| A) | Junction |
| B) | Terminal |
| C) | Loop |
| D) | Node |
7. It is impossible to change the voltage across a capacitor instantly, as this would produce ____ current.
| A) | Low |
| B) | Infinite |
| C) | Zero |
| D) | High |
8. Liquids that are good conductors because of ionization are called
| A) | Acid |
| B) | Bases |
| C) | Electrolytes |
| D) | Electrolytic |
9. When two pure sine waves of the same frequency and the same amplitude which are exactly 180˚ out-of-phase are added together, the result is
| A) | A wave with twice the amplitude |
| B) | Zero signal |
| C) | A wave with half the amplitude |
| D) | A wave with twice the frequency |
10. The temperature-resistance coefficient of pure gold is
| A) | 0.0039 |
| B) | 0.0034 |
| C) | 0.0037 |
| D) | 0.0038 |
11. The presence of an electric current is made known by
| A) | Effects produced |
| B) | Flashing |
| C) | Electric shock |
| D) | Magnetic shock |
12. A trimmer is a variable capacitor in which capacitance is varied by changing the
| A) | Distance between plates |
| B) | Number of plates |
| C) | Plate area |
| D) | Dielectric |
13. The potential gradient in a cable is maximum in
| A) | Uniformly all over |
| B) | Outer sheath |
| C) | Conductor |
| D) | Insulation |
14. The current is ____ times the maximum current at half-power points of a resonance curve.
| A) | 0.632 |
| B) | 1.414 |
| C) | 0.5 |
| D) | 0.707 |
15. In dividing or multiplying phasor quantities,____ form is used.
| A) | Polar |
| B) | Rectangular |
| C) | Trigonometric |
| D) | Exponential |
16. If two equal resistances connected in series across a certain supply are now connected in parallel across the same supply, the power produced will be that of series connection
| A) | Four times |
| B) | One-fourth |
| C) | Two times |
| D) | One-half |
17. What is the efficiency under the conditions of maximum power transfer?
| A) | 25 % |
| B) | 75 % |
| C) | 50 % |
| D) | 100 % |
18. Refers specifically to steady-state values of quantities in ac circuits which are complex numbers.
| A) | Vector quantity |
| B) | Domain |
| C) | Phasor quantity |
| D) | Scalar quantity |
19. What is considered as the most important value of a sine wave?
| A) | Average value |
| B) | Instantaneous value |
| C) | Peak value |
| D) | Effective value |
20. Electric energy refers to
| A) | Volt-ampere |
| B) | Watt divided by time |
| C) | Volt-coulomb |
| D) | Volt divided by coulomb |
21. When two complex conjugates are subtracted, the result is a
| A) | In-phase component |
| B) | Real component |
| C) | Quadrature component only |
| D) | Complex component |
22. A lead conductor has a resistance of 25 Ω at 0 ˚C. Determine its resistance at -30 ˚C
| A) | 22 Ω |
| B) | 24 Ω |
| C) | 11 Ω |
| D) | 12 Ω |
23. What is the total capacitance of 10 capacitors, each of 20 µF in series?
| A) | 200 µF |
| B) | 2 µF |
| C) | 100 µF |
| D) | 0.5 µF |
24. What is the total effective capacitance of two 0.25 µF capacitors connected in series?
| A) | 0.125 µF |
| B) | 1.25 µF |
| C) | 0.50 µF |
| D) | 2.5 if |
25. A 0.09 microfarad capacitor is charged to 220 volts. How long in milliseconds will it discharged resistor has a resistance of 20,000 ohms?
| A) | 0.5 |
| B) | 2.5 |
| C) | 1.5 |
| D) | 1.25 |
26. Norton’s theorem is what form of an ac equivalent circuit?
| A) | Neither voltage nor current |
| B) | Voltage |
| C) | Current |
| D) | Both voltage and current |
27. Which is considered as the effect of a dielectric material?
| A) | Decreasing capacitance |
| B) | Increasing capacitance |
| C) | Increasing the distance between the plates |
| D) | Reducing the working voltage |
28. The reciprocal of a complex number is
| A) | A complex number |
| B) | A whole number |
| C) | An imaginary number |
| D) | A real number |
29. What is a rotating vector whose projection can represent either current or voltage in an ac circuit?
| A) | Velocity |
| B) | Scalar quantity |
| C) | Phasor |
| D) | Polar diagram |
30. If two complex conjugates are added, ___ components results.
| A) | Out-of-phase |
| B) | Quadrature |
| C) | Complex |
| D) | In-phase |
31. When the movable plates of a gang capacitor completely overlap the fixed plates, the capacitance of the capacitor is
| A) | Halfway between maximum and minimum |
| B) | Minimum |
| C) | Maximum |
| D) | Zero |
32. The area of capacitor plates increases two times, then its capacitance
| A) | Decreases two times |
| B) | Decreases four times |
| C) | Increases four times |
| D) | Increases two times |
33. The distance between the capacitor plates increases two times, then its capacitance
| A) | Decreases four times |
| B) | Increases four times |
| C) | Increases two times |
| D) | Decreases two times |
34. Which of the following is neither a basic physical law nor deliverable from one?
| A) | Coulomb’s law |
| B) | Kirchhoff’s second law |
| C) | Ohm’s law |
| D) | Kirchhoff’s first law |
35. What is the peak factor of a triangular wave?
| A) | 1.41 |
| B) | 1.73 |
| C) | 1.11 |
| D) | 1.16 |
36. In a series circuit with unequal resistances the
| A) | Highest R has the highest V |
| B) | Lowest R has the highest I |
| C) | Lowest R has the highest V |
| D) | Highest R has the highest I |
37. Which of the following is the statement of Ohm’s law?
| A) | Electric current is directly proportional to both voltage and resistance |
| B) | Electrical power is directly proportional to both voltage squared and the resistance |
| C) | Electric current varies directly as the voltage and inversely as the resistance |
| D) | Electrical power is directly proportional to the resistance and inversely as the current squared |
38. The usual load of a dc circuit is a/an
| A) | Inductor |
| B) | Both inductor and capacitor |
| C) | Resistor |
| D) | Capacitor |
39. In an RL series circuit,
| A) | Current lags voltage by 180˚ |
| B) | Current leads voltage by 90˚ |
| C) | Current lags voltage by less than 90˚ |
| D) | Current lags voltage by 90˚ |
40. What is the other name of relative permittivity?
| A) | Dielectric strength |
| B) | Breakdown voltage |
| C) | Potential gradient |
| D) | Specific inductance capacity |
41. A capacitor consists of two
| A) | Dielectric separated by a conductor |
| B) | Conductors separated by a dielectric |
| C) | Dielectric only |
| D) | Conductors only |
42. What maximum voltage can be applied across the capacitor for a very short period of time?
| A) | Surge voltage |
| B) | Peak voltage |
| C) | Working voltage |
| D) | Stray voltage |
43. And ideal current source has an internal conductance of _____ siemen(s)
| A) | Infinite |
| B) | One million |
| C) | One |
| D) | Zero |
44. If the capacitance of mica capacitor is 5 times the capacitance of air capacitor, then the relative permittivity of mica is
| A) | 10 |
| B) | 25 |
| C) | 5 |
| D) | 2.5 |
45. The Q-factor of a parallel resonant circuit is also known as
| A) | Resonance magnification factor |
| B) | Current magnification factor |
| C) | Voltage magnification factor |
| D) | Gain magnification factor |
46. What is the reading of an ohmmeter for a shorted capacitor?
| A) | MΩ |
| B) | Zero |
| C) | Infinity |
| D) | kΩ |
47. The symbol Q refers to
| A) | Power quotient |
| B) | Qualification test |
| C) | Quality factor |
| D) | Resonance quotient |
48. At what frequency will an inductor of 5mH have the same reactance as a capacitor of 0.1 µF?
| A) | 7.12 Hz |
| B) | 7.12 kHz |
| C) | 7.12MHz |
| D) | 7.12 GHz |
49. What is the most convenient way of achieving large capacitance?
| A) | By using dielectric of low permittivity |
| B) | By using air as dielectric |
| C) | By using multiplate construction |
| D) | By decreasing distance between plates |
50. The Q-factor of a parallel resonant circuit is also known as
| A) | Load factor |
| B) | Leakage factor |
| C) | Current magnification factor |
| D) | Voltage magnification factor |
51. Which of the following is also known as an anti-resonant circuit?
| A) | Tank circuit |
| B) | Series resonant circuit |
| C) | Tuned circuit |
| D) | Parallel resonant circuit |
52. A series-parallel combination of identical resistors will
| A) | Reduce the voltage rating compared with resistor alone |
| B) | Result in an expensive circuit |
| C) | Increase the voltage rating compared with one resistor alone |
| D) | Increase the power rating compared with one resistor alone |
53. The ratio of the flux density to the electric field intensity in the dielectric is called
| A) | Elasticity |
| B) | Field intensity |
| C) | Permeability |
| D) | Permittivity |
54. Which of the following materials has the lowest dielectric strength?
| A) | Glass |
| B) | Mica |
| C) | Paper |
| D) | Teflon |
55. What refers to the lowest voltage across any insulator that can cause current flow?
| A) | Voltage capacity |
| B) | Breakdown voltage |
| C) | Conduction voltage |
| D) | Critical voltage |
56. What fusion of elements is without chemical action between them?
| A) | Alloy |
| B) | Compound |
| C) | Ionization |
| D) | Mixture |
57. For parallel capacitors, total charge is
| A) | Equal to the charge of either capacitors |
| B) | Equal to the product of the charges |
| C) | The sum of individual charges |
| D) | The quotient of the charges |
58. Which of the following has a positive temperature coefficient?
| A) | Manganin |
| B) | Mica |
| C) | Silicon |
| D) | Carbon |
59. The reason why electrical appliances are connected in parallel.
| A) | All of the answers |
| B) | This makes the operation of appliances independent with each other |
| C) | This results in reduced power consumption |
| D) | It is a simple circuit |
60. If three 100-pF capacitors are connected in series, then the total capacitance is
| A) | 33.3 pF |
| B) | 300 pF |
| C) | 50 pF |
| D) | 100 pF |
61. Rationalizing the denominator of a complex number means
| A) | Adding j component in the denominator |
| B) | Eliminating the j component in the numerator |
| C) | Eliminating the j component in the denominator |
| D) | Adding j component in the numerator |
62. An inductor carries 2 A dc. If its inductance is 100 µH, then what is its inductive reactance?
| A) | Zero |
| B) | -628 Ω |
| C) | 1.3 Ω |
| D) | 628 Ω |
63. The reactance curve is a plot of frequency versus ____ for a series RLC circuit
| A) | Impedance |
| B) | Current |
| C) | Gain |
| D) | Voltage |
64. A capacitor requires 12 µC of charge to raise its potential of 3 V. What is the capacitance of the capacitor?
| A) | 15 µF |
| B) | 36 µF |
| C) | 0.25 µF |
| D) | 4 µF |
65. An impedance is given by 90 ∠-45o is a/an ____ impedance.
| A) | Capacitive |
| B) | Conductive |
| C) | Resistive |
| D) | Inductive |
66. If resonant frequency is 10 kHz and quality factor is 50, then
| A) | R is 50 Ω |
| B) | Bandwidth is 200 Hz |
| C) | XC = is 50,000 Ω |
| D) | XL = is 50,000 Ω |
67. The internal resistance of an ideal current source is
| A) | Equal to the load resistance |
| B) | None of the answers |
| C) | Zero |
| D) | Infinite |
68. If two resistances of 9 Ω and 6 Ω are connected in parallel, the total resistance is
| A) | 15 Ω |
| B) | 3.6 Ω |
| C) | 54 Ω |
| D) | 0.3 Ω |
69. A capacitor is basically constructed of
| A) | Conductors and dielectric |
| B) | Two dielectric separated by a conductor |
| C) | Conductors and semiconductors |
| D) | Two conductors separated by a dielectric |
70. Inductive reactance applies only to sine waves because it
| A) | Decreases with higher frequencies |
| B) | Increases with lower frequencies |
| C) | Depends on the factor 2π |
| D) | Increases with lower inductance |
71. The ohmic value of a resistor with a negative temperature coefficient
| A) | Stays unaffected even with increasing temperature |
| B) | Increase with decreasing temperature |
| C) | Increases with increasing temperature |
| D) | Stays unchanged with temperature change |
72. An open inductor has
| A) | Infinite resistance and zero inductance |
| B) | Infinite resistance and infinite inductance |
| C) | Zero resistance and infinite inductance |
| D) | Zero resistance and zero inductance |
73. Two complex numbers or phasors are said to be conjugate if they
| A) | Are equal in their real components but differ in their quadrature components including algebraic signs. |
| B) | Differ only in the algebraic sign of their quadratic components |
| C) | Differ only in the algebraic sign of their real components |
| D) | Are equal in their real and quadrature components including algebraic signs |
74. When the frequency of an AC wave decreases, the value of XL in a coil
| A) | Stays constant |
| B) | Approaches zero |
| C) | Gets larger negatively |
| D) | Gets larger positively |
75. If a capacitor is rated for 200V dc, what is its effective AC working voltage?
| A) | 100 V |
| B) | 200 V |
| C) | 50 V |
| D) | 400 V |
76. A coil of inductance L has an inductive reactance of XL in 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) | 0 |
| B) | IXL |
| C) | I2XL |
| D) | IXL2 |
77. Of the equivalent combination of units, which one is not equal to watt?
| A) | Ω2/v |
| B) | AV |
| C) | A2Ω |
| D) | J/s |
78. The graph between an alternating quantity and time is called
| A) | Sine wave |
| B) | Curve |
| C) | Waveform |
| D) | A plot |
79. Which one of the following elements serves as a protection against overload?
| A) | Fuse |
| B) | Resistor |
| C) | Relay |
| D) | Switch |
80. An ac series circuit is composed of resistance of 20Ω , the inductive reactance of 40Ω, and a capacitive reactance of 15Ω. If a current of 1 ampere is flowing, what is the applied voltage
| A) | 22 V |
| B) | 220 V |
| C) | 32 V |
| D) | 320 V |
81. A trigger circuit consisting of a capacitor of 0.01 µF is connected in series with a resistor. If the circuit requires 100 Vdc to operate, determine the value of the resistor when time constant is 0.009s.
| A) | 900 KΩ |
| B) | 900 MΩ |
| C) | 900 Ω |
| D) | 900 GΩ |
82. Which of the following is a preferred resistor value?
| A) | 520 |
| B) | 43,000 |
| C) | 47 |
| D) | 54,321 |
83. Which of the following combination of length and the cross-sectional area will give a certain volume of copper the least resistance?
| A) | 2L and1/2 A |
| B) | Does not matter because the volume of copper remains the same |
| C) | ½ L and 2 A |
| D) | L and A |
84. In a resonant circuit, if Q ≥10 resonant frequency ______ bandwidth.
| A) | Bisects |
| B) | Exceeds |
| C) | Is less than |
| D) | Is equal to |
85. Which of the following is a common material used in wire-wound resistors?
| A) | Carbon |
| B) | German silver wire |
| C) | Bronze |
| D) | Manganin |
86. Which of the statements below is not true?
| A) | Voltage source is a passive element |
| B) | Resistor is a linear element |
| C) | Current source is an active element |
| D) | Diode is a non-linear element |
87. What is the most common non-sinusoidal waveform?
| A) | Triangular wave |
| B) | Sawtooth wave |
| C) | Square wave |
| D) | Trapezoidal wave |
88. At what frequency will the current in a series RLC circuit reach its maximum value for an applied voltage of 15 V with R = 500Ω, L = 100 µH and C = 0.001 µF?
| A) | 403 kHz |
| B) | 603 kHz |
| C) | 503 kHz |
| D) | 303 kHz |
89. When two in-phase sine waves that have identical frequency and amplitude are added together, then the result is a sine wave with ____ the amplitude of either.
| A) | Four times |
| B) | Half |
| C) | One-fourth |
| D) | Twice |
90. An open resistor when checked with an ohmmeter reads
| A) | Zero |
| B) | High but within the tolerance |
| C) | Low but not zero |
| D) | Infinite |
91. The ratio between the active power and the apparent power of a load in an ac circuit is called
| A) | Power ratio |
| B) | Quality factor |
| C) | Power reactive |
| D) | Power factor |
92. The internal resistance of an ideal voltage source is
| A) | None of the answer |
| B) | Zero |
| C) | Infinite |
| D) | Equal to the load resistance |
93. A capacitance of 6 µµF means
| A) | 6 aF |
| B) | 6 fF |
| C) | 6 pF |
| D) | 6 nF |
94. In the 5-band method of capacitor color coding, the first band indicates
| A) | Temperature coefficient |
| B) | Tolerance |
| C) | 1st digit |
| D) | Capacitance value |
95. Which of the following is the most popular waveform?
| A) | Square wave |
| B) | Sinusoidal |
| C) | Triangular |
| D) | Sawtooth |
96. In an ac circuit, the power dissipated as heat depends on
| A) | Capacitive reactance |
| B) | Resistance |
| C) | Impedance |
| D) | Inductive reactance |
97. The ratio of maximum value to the effective value of an alternating quantity is called
| A) | Peak factor |
| B) | Leakage factor |
| C) | Form factor |
| D) | Dynamic factor |
98. A series circuit has a ____ power factor at its half-power points
| A) | Lagging |
| B) | Unity |
| C) | Leading |
| D) | Either Leading or Lagging |
99. A linear circuit is one whose parameters
| A) | Change with change in voltage and current |
| B) | Change with change in voltage |
| C) | Do not change with voltage and current |
| D) | Change with change in current |
100. The capacitor opposes any change in voltage across it by
| A) | Acting as a short circuit at time equal to infinity |
| B) | Passing a current proportional to the rate of change of voltage |
| C) | Passing a voltage proportional to the rate of change of current |
| D) | Acting as a short circuit at time equal to zero |
101. Conventional flow assumes charges flow from
| A) | Positive to positive |
| B) | Negative to positive |
| C) | Positive to negative |
| D) | Negative to negative |
102. What is the reciprocal of quality factor?
| A) | Power factor |
| B) | 1/Q factor |
| C) | Dissipation factor |
| D) | Reactive factor |
103. Which of the following elements is active?
| A) | Capacitor |
| B) | Inductor |
| C) | Ideal voltage source |
| D) | Resistor |
104. A real current source has
| A) | Infinite internal resistance |
| B) | Small internal resistance |
| C) | Zero internal resistance |
| D) | Large internal resistance |
105. Which factor does not affect resistance?
| A) | Mass |
| B) | Resistivity |
| C) | Length |
| D) | Cross-sectional area |
106. Points to be considered in choosing a capacitor
| A) | All of the answers |
| B) | Capacitance |
| C) | Type of dielectric |
| D) | Working voltage |
107. What is the specific resistance of a pure germanium?
| A) | 55 k-Ω |
| B) | 55 Ω-mm |
| C) | 55 Ω-m |
| D) | 55 Ω-cm |
108. In a rectangular wave, the peak factor is
| A) | 1.0 |
| B) | 1.16 |
| C) | 1.73 |
| D) | 1.11 |
109. For multi-plate capacitor, capacitance is proportional to
| A) | Number of plates plus one(n + 1) |
| B) | Number of plates (n) |
| C) | Number of plates less one(n – 1) |
| D) | Number of plates less two(n – 2) |
110. A resistor wound with a wire doubled back on itself to reduce the inductance.
| A) | Bleeder resistor |
| B) | Wire-wound resistor |
| C) | Bifilar resistor |
| D) | Anti-inductive resistor |
111. What theorem is usually used in the analysis of the transistor circuit?
| A) | Thevenin’s theorem |
| B) | Superposition theorem |
| C) | Millman’s theorem |
| D) | Norton’s theorem |
112. What theorem is generally used in the analysis of vacuum tubes?
| A) | Thevenin’s theorem |
| B) | Millman’s theorem |
| C) | Superposition theorem |
| D) | Norton’s theorem |
113. Which of the following is not a factor affecting dielectric strength?
| A) | Mass |
| B) | Temperature |
| C) | Moisture content |
| D) | Thickness |
114. What refers to such work at very low temperatures, near absolute zero?
| A) | Superconductivity |
| B) | Subsonic |
| C) | Cryogenics |
| D) | Thermionic |
115. In adding or subtracting phasor quantities, ____ form is the most convenient.
| A) | Trigonometric |
| B) | Rectangular |
| C) | Polar |
| D) | Exponential |
116. An electric circuit contains
| A) | Both active and passive elements |
| B) | Active elements |
| C) | Reactive elements |
| D) | Passive elements |
117. If the voltage across the plates of 2 F capacitor is increased by 4 V, then charge on the plates will
| A) | Decrease by 4 C |
| B) | Increase by 4 C |
| C) | Increase by 2 C |
| D) | Decrease by 2 C |
118. What is the total resistance of a two equal valued resistors in series?
| A) | Twice as one |
| B) | The sum of their reciprocals |
| C) | The difference of both |
| D) | The product of both |
119. The charge in the capacitor is stored at the
| A) | Plates |
| B) | Terminals |
| C) | Dielectric |
| D) | Air |
120. The voltage lags the current by π/2 cycle in a
| A) | Purely inductive circuit |
| B) | Purely capacitive circuit |
| C) | Circuit containing resistance, capacitance and inductance |
| D) | Purely resistive circuit |
121. What is the purpose of a load in an electric circuit?
| A) | To make the circuit complete |
| B) | To utilize electrical energy |
| C) | To increase the circuit current |
| D) | To decrease the circuit current |
122. How many coulombs are delivered by a storage battery in 25 hours if it is supplying current at the rate of 3 A?
| A) | 2.592 x 103 C |
| B) | 2.592 x 105 C |
| C) | 2.592 x 108 C |
| D) | 2.592 x 1012 C |
123. Which of the following capacitors has the highest cost per µF?
| A) | Air |
| B) | Mica |
| C) | Plastic |
| D) | Electrolytic |
124. The curve between current and frequency is termed as
| A) | Power curve |
| B) | Gain curve |
| C) | Resonance curve |
| D) | Voltage curve |
125. A capacitor of 0.5 µF charged to 220 V is connected across an uncharged 0.5 µF capacitor. What is the voltage across each capacitor?
| A) | 22 V |
| B) | 220 V |
| C) | 110 V |
| D) | 150 V |
126. Leakage resistance in a capacitor results into
| A) | Short-circuiting |
| B) | Internal heating |
| C) | Internal bleeding |
| D) | Shorter useful life |
127. Effects of capacitance
| A) | Voltage is lagged behind the current by a quarter cycle |
| B) | All of the answers |
| C) | Electric energy is stored in the capacitor in the form of electrostatic field |
| D) | It opposes any change in the amount of voltage |
128. A capacitor opposes change in
| A) | Voltage and current |
| B) | Neither voltage nor current |
| C) | Voltage |
| D) | Current |
129. Another term of the quality factor of the resonant circuit.
| A) | Figure of demerit |
| B) | Figure of merit |
| C) | Noise factor |
| D) | Noise figure |
130. What is the value of a carbon composition resistor with the following color code: Brown, white, orange, red
| A) | 1.9 KΩ; 2 % |
| B) | 19 KΩ; 2 % |
| C) | 19 KΩ; 20 % |
| D) | 190 Ω; 10 % |
131. In a complex resistance-reactance plane, XL is represented
| A) | By an axis perpendicular to the XC axis |
| B) | By an axis opposite the XC axis |
| C) | By an axis opposite the R axis |
| D) | By an axis parallel to the R axis |
132. What determines the direction of induced emf in a conductor or coil?
| A) | Fleming’s right hand rule |
| B) | Ampere’s circuital law |
| C) | Cork screw rule |
| D) | Fleming’s left hand rule |
133. What is the temperature coefficient of the resistance Eureka?
| A) | Almost zero |
| B) | Negative |
| C) | Positive |
| D) | Infinity |
134. What is the conductance of a circuit having three 10Ω resistors in parallel?
| A) | 0.33 S |
| B) | 3.33 S |
| C) | 30 S |
| D) | 0.3 S |
135. A tank circuit is a
| A) | A non-resonant circuit |
| B) | Series LC circuit |
| C) | A resonant circuit |
| D) | Parallel LC circuit |
136. A term used to express the amount of electrical energy stored in electrostatic field.
| A) | Coulombs |
| B) | Watts |
| C) | Electron-volt |
| D) | Joules |
137. For a triangular and sawtooth waveform the rms voltage or current equals
| A) | 0.707 times peak value |
| B) | 0.577 times peak value |
| C) | 0.707 times rms value |
| D) | 0.577 times average value |
138. An inductive load always has a ____ power factor
| A) | Leading |
| B) | Zero |
| C) | Lagging |
| D) | Unity |
139. When the net reactance in a series coil-capacitor circuit is zero at frequency f, the nature of its reactance of frequency 2f is
| A) | Infinite |
| B) | Inductive |
| C) | Resistive |
| D) | Capacitive |
140. In an ac wave, 30 degrees of phase is ___ of a cycle.
| A) | 1/3 |
| B) | 1/2 |
| C) | 1/12 |
| D) | 1/30 |
141. In a multiple capacitor, the plate area is
| A) | Increased |
| B) | The same |
| C) | Decreased |
| D) | Variable |
142. Two capacitors of capacitance 9 µF and 18 µF in series will have a total capacitance of
| A) | 180 µF |
| B) | 27 µF |
| C) | 162 µF |
| D) | 6 µF |
143. In an ac circuit with XL and R in series, the
| A) | Voltage across R lags the voltage across XL by 90° |
| B) | Voltages across R and XL are in phase |
| C) | Voltage across R leads the voltage across XL by 90° |
| D) | Voltages across R and XL are 180° out-of-phase |
144. Kirchhoff’s laws (KCL and KVL) are applicable to
| A) | DC as well as AC circuits |
| B) | AC circuits |
| C) | DC circuits |
| D) | Passive networks alone |
145. Which of the following is the peakiest?
| A) | Rectangular wave |
| B) | Square wave |
| C) | Sinusoidal wave |
| D) | Triangular wave |
146. When two coils of identical reactance are in parallel without mutual inductance, the reactance of the combination is ____ the reactance of each coil.
| A) | One fourth |
| B) | Four times |
| C) | Twice |
| D) | One half |
147. What is the resonant frequency of a circuit when L of 3 microhenrys and C of 40 picofarads are in series?
| A) | 14.5 kHz |
| B) | 145 kHz |
| C) | 14.5 MHz |
| D) | 145 MHz |
148. An alloy composed of 84 % copper, 12 % manganese and 4 % nickel.
| A) | Manganin |
| B) | Nichrome |
| C) | Constantan |
| D) | German silver wire |
149. 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) | Impedance chart |
| C) | Reactance chart |
| D) | Resonance chart |
150. In a series RLC circuit
| A) | XL leads XC by 90˚ |
| B) | The current leads VL by 90˚ |
| C) | Z =jXL at resonance |
| D) | The current lags VL by 90˚ |
151. A capacitor is used to
| A) | Block dc current |
| B) | Short the voltage source |
| C) | Pass dc current |
| D) | Open voltage source |
152. Which waveform in which the RMS value and the mean value are equal?
| A) | Sawtooth |
| B) | Sine wave |
| C) | Square wave |
| D) | Triangular wave |
153. The voltage cannot be exactly in phase with the current in a circuit that contains
| A) | Inductance, capacitance and resistance |
| B) | Inductance and capacitance |
| C) | Only resistance |
| D) | Only capacitance |
154. A factor that states how much the resistance changes for a change in temperature?
| A) | Resistivity |
| B) | Coefficient of temperature change |
| C) | Temperature coefficient of resistance |
| D) | Specific resistance |
155. The ratio between the reactive power and the apparent power of an ac load is called
| A) | Reactive power |
| B) | Quality factor |
| C) | Power ratio |
| D) | Power factor |
156. If the output resistance of a voltage source is 4Ω, it internal resistance should be
| A) | 2Ω |
| B) | None of the answers |
| C) | 4Ω |
| D) | 8Ω |
157. In an inductive coil, the rate of rise of current is maximum
| A) | After one time constant |
| B) | Near the final maximum value of current |
| C) | At mid-value of current |
| D) | At half-power points |
158. In an ac circuit with inductive reactance, the
| A) | Current through the inductance and voltage across it are 180˚ out-of-phase |
| B) | Voltage across the inductance must be 90˚ out-of-phase with the applied voltage |
| C) | Phase angle of the circuit is always 45˚ |
| D) | Current through the inductance lags its induced voltage by 90˚ |
159. An inductance of 1 mH is
| A) | 0.001 H |
| B) | 0.10 H |
| C) | 0.0001 H |
| D) | 0.01 H |
160. 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) | Frequency |
| B) | Phase |
| C) | Waveform |
| D) | Amplitude |
161. A capacitive load always has a ____ power factor
| A) | Unity |
| B) | Leading |
| C) | Zero |
| D) | Lagging |
162. A rheostat is a form of
| A) | Variable resistor |
| B) | Potentiometer |
| C) | Variable capacitor |
| D) | Thermocouple |
163. Which of the following does not affect resistance?
| A) | Length |
| B) | Mass |
| C) | Cross-sectional area |
| D) | Resistivity |
164. Which of the following has negative temperature coefficient?
| A) | Brass |
| B) | Carbon |
| C) | Constantan |
| D) | Nickel |
165. Capacitance increase with
| A) | Higher values of applied voltage |
| B) | Smaller plate area and less distance between plates |
| C) | Larger plate area and greater distance between plates |
| D) | Larger plate area and less distance between plates |
166. Form its definition, the unit of electric field, is the N/C and equivalent unit of
is the
| A) | V(m) |
| B) | Vm2 |
| C) | V/m |
| D) | V/m2 |
167. What is the peak factor for alternating current or voltage varying sinusoidally?
| A) | 1.11 |
| B) | 0.636 |
| C) | 0.707 |
| D) | 1.4142 |
168. The charging of a capacitor through a resistance obeys
| A) | Square law |
| B) | Linear law |
| C) | Logarithmic law |
| D) | Exponential law |
169. Barium-strontium titanite dielectric material is also called
| A) | Polyster |
| B) | Ceramic |
| C) | Electrolytic |
| D) | Bakelite |
170. Transient period is considered over after
| A) | 1 |
| B) | 100 |
| C) | 6 |
| D) | 5 |
171. What is the form factor of a triangular wave?
| A) | 1.11 |
| B) | 1.41 |
| C) | 1.16 |
| D) | 1.73 |
172. Which of the following does not generally affect the value of a capacitor?
| A) | The surface area of the plates |
| B) | The thickness of the dielectric |
| C) | The voltage applied to the plate |
| D) | The dielectric material used |
173. Why are inductance and capacitance not relevant in a dc circuit?
| A) | Because they do not exist in a dc circuit |
| B) | Because it is a simple circuit |
| C) | Because dc circuits require only resistance as load |
| D) | Because frequency of dc is zero |
174. At parallel resonance, the currents flowing through L and C are
| A) | Zero |
| B) | Unequal |
| C) | Equal |
| D) | Infinite |
175. The capacitance of a capacitor is _____ relative permittivity.
| A) | Inversely proportional to |
| B) | Inversely proportional to the square of |
| C) | Equal to |
| D) | Directly proportional to |
176. “Any resistance R in a branch of a network in which a current I is flowing can be replaced by a voltage equal to IR”. This states
| A) | Compensation theorem |
| B) | Millman’s theorem |
| C) | Reciprocity theorem |
| D) | Superposition theorem |
177. The reason why electrical appliances are not connected in series.
| A) | All of the answers |
| B) | Greater electrical power saving |
| C) | Appliances have different current ratings |
| D) | Power loss is minimum |
178. For a series AC circuit, _____ is not used as a reference phasor.
| A) | Current |
| B) | Voltage |
| C) | Conductance |
| D) | Impedance |
179. In a complex number 5 + j 10, 10 is called _____ part.
| A) | Imaginary |
| B) | Real |
| C) | Conjugate |
| D) | Integer |
180. An inductive circuit of resistance 16.5Ω and inductance of 0.14 H takes a current of 25 A. if the frequency is 50 Hz, find the supply voltage.
| A) | 991 V |
| B) | 1501 V |
| C) | 1877 V |
| D) | 1174 V |
181. If a certain circuit has a current that is lagging the voltage by 45˚, then it displays
| A) | Pure capacitive reactance |
| B) | Resistance and inductive reactance |
| C) | Pure inductive reactance |
| D) | Resistance and capacitance reactance |
182. For maximum power transfer, 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 |
183. Which of the following is a disadvantage of a wire-wound resistor?
| A) | It has reactance in radio-frequency circuits |
| B) | It cannot handle high voltage |
| C) | It draws a large amount of current |
| D) | It cannot handle much power |
184. Which of the following represents the energy stored in a capacitor?
| A) | CV2/2 |
| B) | C2/V |
| C) | CV |
| D) | 2Q2/C |
185. For a carbon composition resistor, typical resistance values range from
| A) | 2.7Ω to 2.7GΩ |
| B) | 1000Ω to 10000Ω |
| C) | 10Ω to 10MΩ |
| D) | 2.7Ω to 22MΩ |
186. A three-by-three, series-parallel matrix of resistors, all having the same ohmic value, would have a net resistance of
| A) | The same value as a single resistor |
| B) | Nine times the value of a single resistor |
| C) | One-third the value of a single resistor |
| D) | Three times the value of a single resistor |
187. What is the cross-sectional are of a conductor whose diameter is 0.001 inch?
| A) | One micron |
| B) | One circular mil |
| C) | One angstrom |
| D) | One steradian |
188. Which of the following describes the action of a capacitor?
| A) | Stores electrical energy |
| B) | Opposes changes in current flow |
| C) | Converts ac to dc |
| D) | Creates a dc resistance |
189. In liquids and gases, ionization current results from a flow of
| A) | Positive or negative ions |
| B) | Ions that are lighter in weight than electrons |
| C) | Protons |
| D) | Free electrons |
190. The wavelength of an alternating waveform depends upon the ____ of the variation.
| A) | Period |
| B) | Frequency |
| C) | Amplitude |
| D) | Number |
191. What is the half-power bandwidth of a parallel resonant circuit which has a resonant frequency of 3.6 MHz and Q of 218?
| A) | 16.5 MHz |
| B) | 1.65 kHz |
| C) | 165 kHz |
| D) | 16.5 kHz |
192. A wire of one kilometre length has a resistance of 20Ω. If the length is halved, then the new resistance is ____ the original resistance.
| A) | Half |
| B) | One-fourth |
| C) | Three times |
| D) | Twice |
193. The value of temperature coefficient (a) is dependent upon
| A) | The volume of the material |
| B) | The nature of material and temperature |
| C) | The cross-sectional area of the material |
| D) | The length of material |
194. When capacitors are connected in series, the total capacitance is
| A) | Greater than the largest capacitor |
| B) | Smaller than the smallest capacitor |
| C) | Greater than any of the capacitor |
| D) | Smaller than the largest capacitor |
195. A law which states that when a constant electromotive force is applied to a circuit consisting of a resistor and capacitor connected in series, the time taken for the potential on the plates of the capacitor to rise to any given fraction of its final value depends only on the product of capacitance and resistance.
| A) | CR law |
| B) | Child’s law |
| C) | Debye T3 law |
| D) | Coulomb’s law |
196. Which of the following is not considered a physical factor affecting resistance?
| A) | Length |
| B) | Material type |
| C) | Cross-sectional |
| D) | Temperature |
197. 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 |
198. What is the hot resistance of a 100 W, 220 V incandescent lamp?
| A) | 22Ω |
| B) | 484Ω |
| C) | 2.2Ω |
| D) | 4.84Ω |
199. As applied to a series RLC circuit, bandwidth means
| A) | The frequency at which XL = XC |
| B) | The difference between the highest and lowest frequencies of the oscillator |
| C) | The frequency range for maximum power transfer |
| D) | The separation of the half-power points |
200. When the temperature of copper wire is increased its resistance is
| A) | Increased |
| B) | Constant |
| C) | Zero |
| D) | Decreased |
201. Property of an electric circuit that dissipates electric energy
| A) | Conductance |
| B) | Impedance |
| C) | Resistance |
| D) | Reactance |
202. The superposition theorem is used when the circuit contains
| A) | Reactive elements |
| B) | Single voltage source |
| C) | Active elements |
| D) | Number of voltage sources |
203. What is the time constant for L of 240 mH in series with R of 20Ω?
| A) | 12 s |
| B) | 83.3 s |
| C) | 4.8 s |
| D) | 12 ms |
204. A 5 µF capacitor charge to 5V has a stored charge equal to
| A) | 200 µc |
| B) | 25 µc |
| C) | 5 µc |
| D) | 1 µc |
205. What is the reciprocal of capacitance?
| A) | Susceptance |
| B) | Elastance |
| C) | Conductance |
| D) | Reluctance |
206. What does a capacitor store?
| A) | Current |
| B) | Charge |
| C) | Power |
| D) | Voltage |
207. What determines the magnitude of electric current?
| A) | The rate at which electrons pass a given point |
| B) | The type of material used |
| C) | The rate at which electrons are produced |
| D) | The current carrying capacity of the circuit |
208. The second strip of an electronic resistor color-code represents
| A) | The tolerance |
| B) | The second digit of the value |
| C) | The temperature |
| D) | The multiplier |
209. The electric field strength between capacitor plates has a unit of
| A) | Amperes per mil |
| B) | Volts per mil |
| C) | Volts per meter |
| D) | Amperes per meter |
210. Series resonant circuit is sometimes known as
| A) | Inductive circuit |
| B) | Acceptor circuit |
| C) | Rejector circuit |
| D) | Capacitive circuit |
211. Loop currents should be assumed to flow in which direction
| A) | Straight |
| B) | Clockwise |
| C) | Counter-clockwise |
| D) | Either Clockwise or Counter-clockwise arbitrarily selected |
212. In a circuit, a passive element is one which
| A) | Supplies energy |
| B) | Receives energy |
| C) | Attenuates signal |
| D) | Both supplies and receives energy |
213. A circuit whose parameters change with voltage or current.
| A) | Non-linear circuit |
| B) | Passive circuit |
| C) | Linear circuit |
| D) | Complex circuit |
214. A gang capacitor is a variable capacitor in which capacitance is varied by changing the
| A) | Dielectric |
| B) | Number of plates |
| C) | Distance between plates |
| D) | Plate area |
215. The charging of a capacitor through a resistance follows what law?
| A) | Linear law |
| B) | Inverse-square law |
| C) | Hyperbolic law |
| D) | Exponential law |
216. If a coil has a Q of 10, it means that
| A) | It is a low Q coil |
| B) | The energy stored in the magnetic field of the coil is 10 times the energy wasted in its resistance |
| C) | The energy wasted in its resistance is 10 times the energy stored in the magnetic field of the coil |
| D) | It is a high Q coil |
217. What is the resonant frequency of a circuit when L of 25 microhenrys and C of 10 picofarads are in parallel?
| A) | 10.1 kHz |
| B) | 101 kHz |
| C) | 10.1 MHz |
| D) | 101 MHz |
218. If one resistance in a series connection is open, then
| A) | The voltage is zero across the open resistance |
| B) | The current is zero in all the other resistances |
| C) | The voltage is infinite across the open resistance |
| D) | The current is maximum in all the other resistances |
219. In a series RLC circuit
| A) | Impedance will always decrease |
| B) | Increasing the frequency decreases the resistance |
| C) | Both XL and XC change as frequency changes |
| D) | Increasing the frequency increases the resistance |
220. Tungsten filament of bulbs has a hot resistance higher than its cold resistance due to its temperature coefficient which is
| A) | Zero |
| B) | Negative |
| C) | Positive |
| D) | Infinite |
221. Which statement is true about a passive circuit?
| A) | A circuit with a voltage source |
| B) | A circuit with a current source |
| C) | A circuit with only resistance as a load |
| D) | A circuit with neither a source of current nor a source of potential difference |
222. When two unequal values of resistors are connected in parallel across a dc source, greater current flows through the
| A) | Higher wattage resistance |
| B) | Lower resistance |
| C) | Lower wattage resistance |
| D) | Higher resistance |
223. What is the rms value of a square wave?
| A) | Equals its peak-to-peak value |
| B) | Peak divided by square root of two |
| C) | Peak divided by pi |
| D) | Equals its peak value |
224. What rating of a resistor determines its ability to absorb heat?
| A) | Voltage |
| B) | Ohmic |
| C) | Current |
| D) | Wattage |
225. The impedance in the study of electronics is represented by resistance and
| A) | Inductance and capacitance |
| B) | Inductance |
| C) | Capacitance |
| D) | Reactance |
226. The ratio of W/VA in an ac circuit means
| A) | Load factor |
| B) | Reactive factor |
| C) | Quality factor |
| D) | Power factor |
227. The Q-factor of a series resonant circuit is also known as
| A) | Leakage factor |
| B) | Load factor |
| C) | Voltage magnification factor |
| D) | Current magnification factor |
228. If the inductance is decreased, the impedance of the circuit containing a resistor a capacitor and an inductor connected in series to an ac source
| A) | Decreases, increases or remains the same |
| B) | Increases |
| C) | Decreases or increases |
| D) | Decreases |
229. Which of the following capacitors is suitable for DC filter circuits?
| A) | Mica |
| B) | Paper |
| C) | Electrolytic |
| D) | Ceramic |
230. With double the number of turns by the same length and area, the inductance is
| A) | Quadrupled |
| B) | Doubled |
| C) | Quartered |
| D) | The same |
231. When voltage is applied across a ceramic dielectric the electrostatic field produced is 50 times greater than air dielectric. The dielectric constant of ceramic therefore is
| A) | 100 |
| B) | 16.67 |
| C) | 5 |
| D) | 50 |
232. Metal tin becomes a superconductor at approximately
| A) | 3.7 K |
| B) | 5 K |
| C) | 6 K |
| D) | 4.7 K |
233. For a series circuit, the higher the quality factor
| A) | The narrower the passband |
| B) | The greater the bandwidth |
| C) | The wider the passband |
| D) | The broader the resonance curve |
234. For greater accuracy, the value of phase angle should be determined from
| A) | Cosθ |
| B) | Sinθ |
| C) | Tanθ |
| D) | Secθ |
235. The factor 0.707 for converting peak to RMS applies only to
| A) | Sine waves |
| B) | Triangle waves |
| C) | Sawtooth waves |
| D) | Square waves |
236. The reason why alternating current can induce voltage is
| A) | It has high peak value |
| B) | It has a constant magnetic field |
| C) | It has a varying magnetic field |
| D) | It has a stronger magnetic field than direct current |
237. Norton’s theorem is ____ Thevenin’s theorem.
| A) | The converse of |
| B) | More accurate than |
| C) | Older that |
| D) | The same as |
238. For a parallel AC circuit, ____ is used as a reference phasor.
| A) | Resistance |
| B) | Voltage |
| C) | Power |
| D) | Current |
239. An intermittent and non-symmetrical alternating current like that obtained from the secondary winding of an induction coil
| A) | Inductive current |
| B) | Capacitive current |
| C) | Faradic current |
| D) | Transient ac current |
240. If a multiplate capacitor has 10 plates, each of area 10 cm2, then
| A) | 10 capacitors will be in parallel |
| B) | 9 capacitors will be in series |
| C) | 10 capacitors will be in series |
| D) | 9 capacitors will be in parallel |
241. For a linear circuit, ____ voltage or current is used to calculate average power.
| A) | Average |
| B) | Instantaneous |
| C) | Peak |
| D) | Rms |
242. In a circuit, an active element is one which
| A) | Both supplies and receives energy |
| B) | Receives energy |
| C) | Supplies energy |
| D) | Amplifies signal |
243. The maximum power transfer theorem is used in
| A) | Power system |
| B) | Electronic system |
| C) | Refrigeration |
| D) | Air conditioning |
244. Which of the following dielectric materials makes the highest-capacitance capacitor?
| A) | Electrolyte |
| B) | Mica |
| C) | Barium-strontium titanite |
| D) | Air |
245. Which of the following dielectric materials makes the lowest-capacitance capacitor?
| A) | Air |
| B) | Mica |
| C) | Paper |
| D) | Electrolyte |
246. The unit of elastance is
| A) | Henry |
| B) | Siemen |
| C) | Daraf |
| D) | Farad |
247. What dielectric is generally employed by a variable capacitor?
| A) | Electrolyte |
| B) | Air |
| C) | Ceramic |
| D) | Mica |
248. Which of the following is a way of decreasing mutual inductance?
| A) | Increasing the number of turns of either coil |
| B) | Decreasing the number of turns of either coil |
| C) | Moving the coils apart |
| D) | Moving the coils closer |
249. Permeability is otherwise known as
| A) | Magnetic conductivity |
| B) | Magnetic susceptibility |
| C) | Electric conductivity |
| D) | Electric susceptibility |
250. What is expected when two 20KΩ, 1 watt resistor in parallel are use instead of one 10KΩ, 1 watt?
| A) | Provides less power |
| B) | Provides more power |
| C) | Provides higher current |
| D) | Provides wider tolerance |
251. The power factor of a circuit is equal to
| A) | R/Z |
| B) | RZ |
| C) | XL/Z |
| D) | XC/Z |
252. The result of rust in electrical (wire) connection is
| A) | Conductance |
| B) | Resistance |
| C) | Impedance |
| D) | Inductance |
253. When capacitors are connected in parallel, the total capacitance is
| A) | Greater than the smallest capacitor |
| B) | Greater than the largest capacitor |
| C) | Smaller than the smallest capacitor |
| D) | Smaller than the largest capacitor |
254. A series RL circuit has R of 10Ω and XL of 5Ω, its impedance in rectangular form is given by
| A) | 10 – j 10Ω |
| B) | 10 + j 10Ω |
| C) | 10 – j 5Ω |
| D) | 10 + j 5Ω |
255. A capacitance of 0.05 µF equals
| A) | 0.05 x 10-12 F |
| B) | 0.05 x 1012 F |
| C) | 0.05 x 10-6 F |
| D) | 0.05 x 106 F |
256. Thevenin’s theorem is what form of an equivalent circuit?
| A) | Current |
| B) | Voltage |
| C) | Both current and voltage |
| D) | Neither current nor voltage |
257. When current and voltage are in phase in an ac circuit, the ____ is equal to zero.
| A) | Inductance |
| B) | Capacitance |
| C) | Reactance |
| D) | Resistance |
258. When the power factor of a circuit is zero,
| A) | Power absorbed is maximum |
| B) | The impedance is minimum |
| C) | Power absorbed is minimum |
| D) | Power absorbed is zero |
259. Which of the following is not a factor affecting the capacitance of a basic capacitor?
| A) | Dielectric material used |
| B) | Distance between plates |
| C) | Number of plates |
| D) | Area of plates |
260. Delta to wye or wye to delta transformation technique is applied to a ___ network.
| A) | Complex |
| B) | Two-terminal |
| C) | Three-terminal |
| D) | One-terminal |
261. Refers to the outward-curving distortion of the lines of force near the edges of two parallel metal plates that form a capacitor.
| A) | Skin effect |
| B) | Hall effect |
| C) | Edge effect |
| D) | Night effect |
262. Voltage resonance means
| A) | Series resonance |
| B) | Gain magnification |
| C) | Current magnification |
| D) | Parallel resonance |
263. Resistor with colored bands in the body
| A) | Rheostat |
| B) | Potentiometer |
| C) | Wire-wound resistor |
| D) | Carbon-composition resistor |
264. How many degrees of phase represent one full cycle?
| A) | 180 |
| B) | 360 |
| C) | 270 |
| D) | 90 |
265. Series resonance occurs when
| A) | Both XL = XC and Z = R |
| B) | XL = XC |
| C) | Z = R |
| D) | XL = R |
266. The average value of a triangular or sawtooth wave is ___ times its peak value.
| A) | 0.577 |
| B) | 0.500 |
| C) | 0.318 |
| D) | 0.637 |
267. A series RLC circuit consists of a 10Ω resistor in series with L = 10 µH, and C = 100 µF.
Determine a new value of I, for which the resonant frequency is one–half the original value.
| A) | 40 µH |
| B) | 40 mH |
| C) | 40 pH |
| D) | 40 nH |
268. What is the specific resistance of a pure silicon?
| A) | 55 Ω-m |
| B) | 55 Ω-mm |
| C) | 55 Ω-cm |
| D) | 55 KΩ-m |
269. In a parallel bank with unequal branch resistances
| A) | The highest R has the highest I |
| B) | The lowest R has the highest V |
| C) | The highest R has the highest V |
| D) | The lowest R has the highest V |
270. The arc across a switch when it open an RL circuit is a result of the
| A) | Large self-induced voltage across L |
| B) | Low resistance of the open switch |
| C) | Long time constant |
| D) | Surge of resistance |
271. The temperature coefficient of resistance of electrolytes is
| A) | Negative |
| B) | Infinite |
| C) | Zero |
| D) | Positive |
272. What is the complex impedance of a circuit with an absolute resistance of 300Ω
| A) | 0 – j 300Ω |
| B) | 300 + j 0Ω |
| C) | 0 + j 300Ω |
| D) | 300 + j 90Ω |
273. If an emf in circuit A produces a current in circuit B, then the same emf in circuit B produces the same current in circuit A. this theorem is known as
| A) | Reciprocity theorem |
| B) | Maximum power transfer theorem |
| C) | Norton’s theorem |
| D) | Millman’s theorem |
274. High resistance values are a consequence of the____ of the film.
| A) | Thinness |
| B) | Thickness |
| C) | Length |
| D) | Area |
275. In Norton’s theorem, the short circuit current is obtained by
| A) | Shorting the voltage source |
| B) | Opening the voltage source |
| C) | Shorting the load terminals |
| D) | Opening the load terminals |
276. Which of the following capacitors are used only in dc circuits?
| A) | Mylar |
| B) | Ceramic |
| C) | Electrolytic |
| D) | Mica |
277. The RMS value of a triangular or sawtooth waveform is ___ times its peak value.
| A) | 0.577 |
| B) | 0.25 |
| C) | 0.707 |
| D) | 0.500 |
278. When resistance are connected in parallel, the total resistance is
| A) | Increasing and decreasing depending upon the supply voltage |
| B) | Less than the smallest resistance in the connection |
| C) | Between the smallest and greatest resistance in the connection |
| D) | Greater than the smallest resistance in the connection |
279. Parallel resonant circuit is sometimes called as
| A) | Rejector circuit |
| B) | Acceptor circuit |
| C) | Capacitive circuit |
| D) | Inductive circuit |
280. If three 9 mH inductors are connected in parallel without mutual inductance then the total inductance is
| A) | 27 mH |
| B) | 18 mH |
| C) | 3 mH |
| D) | 9 mH |
281. Which of the following conditions is not true for a series RLC circuit at resonance?
| A) | The magnitude of Z is √{R2 + (XL - XC)2} |
| B) | XL = XC |
| C) | Z = jXL |
| D) | The power factor is one |
282. In a rectangular wave, the form factor is
| A) | 1.11 |
| B) | 1.0 |
| C) | 1.73 |
| D) | 1.16 |
283. A neon glow lamp used as a night light ionizes at approximately
| A) | 100 V |
| B) | 80 V |
| C) | 70 V |
| D) | 90 V |
284. The farad is not equivalent to which of the following combination of units
| A) | J/V2 |
| B) | C/V |
| C) | CV2 |
| D) | C2/J |
285. According to Gauss theorem, flux can be equated to
| A) | Field intensity |
| B) | Voltage |
| C) | Charge |
| D) | Current |
286. Electron flow assumes charges flow from
| A) | Positive to positive |
| B) | Negative to positive |
| C) | Positive to negative |
| D) | Negative to negative |
287. The open-circuit voltage at the terminal of load RL is 60V. Under the condition of maximum power transfer, the load voltage will be
| A) | 15 V |
| B) | 60 V |
| C) | 30 V |
| D) | 20 V |
288. The mutual inductance between two coils is ___ the reluctance of magnetic path.
| A) | Equal to |
| B) | Independent to |
| C) | Inversely proportional to |
| D) | Directly proportional to |
289. The hot resistance of an incandescent lamp is about ___ times its cold resistance.
| A) | 50 |
| B) | 10 |
| C) | 100 |
| D) | 5 |
290. VL = VC in a series RLC circuit when
| A) | The value of the impedance is minimum |
| B) | The current leads the total voltage by 90˚ |
| C) | The power factor is zero |
| D) | The total voltage is zero |
291. What value of R is needed with a 0.05 µF C for an RC time constant of 0.02 s?
| A) | 400 KΩ |
| B) | 400 MΩ |
| C) | 400 GΩ |
| D) | 400 Ω |
292. Which of the following does not refer to electrical energy?
| A) | Volt-ampere |
| B) | Watt-second |
| C) | Volt-coulomb |
| D) | Joule |
293. What increases the resistance of wire at high frequencies?
| A) | Voltage |
| B) | Skin effect |
| C) | Temperature |
| D) | Insulation |
294. The power factor of a certain circuit in which the voltage lags behind the current is 80 %. To increase the power to 100 %, it is necessary to add ___ to the circuit.
| A) | Impedance |
| B) | Inductance |
| C) | Resistance |
| D) | Capacitance |
295. In a pure capacitance,
| A) | Current lags voltage by 90˚ |
| B) | Current lags voltage by 180˚ |
| C) | Current leads voltage by 180˚ |
| D) | Current leads voltage by 90˚ |
296. Under the conditions of maximum power transfer, a voltage source is delivering a power of 15 W to the load. What is the power generated by the source?
| A) | 30 W |
| B) | 15 W |
| C) | 4 W |
| D) | 60 W |
297. The resistance of an insulator ___ when its temperature is increased.
| A) | Increases |
| B) | Varies |
| C) | Decreases |
| D) | Remains the same |
298. For series capacitors, total charge is
| A) | The quotient of the charges |
| B) | Equal to the product of the charges |
| C) | Equal to the charge of either capacitors |
| D) | The sum of individual charges |
299. In an ac circuit with a resistive branch and an inductive branch in parallel, the
| A) | Resistive and inductive branch currents have the same phase |
| B) | Resistive branch current is 90° out of phase with the inductive branch current |
| C) | Resistive and inductive branch currents are 180° out-of-phase |
| D) | Voltage across the inductance leads the voltage across the resistance by 90° |
300. A switch designed to have low capacitance between its terminal when open.
| A) | Capacitance switch |
| B) | AntiLOCAP switch |
| C) | Anticapacitance switch |
| D) | LOCAP switch |
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