McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Electrical Engineering .
Chapters
| 51. |
The capacity of capacitor bank used in power factor correction is expressed in terms of |
| A. | kW |
| B. | kVA |
| C. | kVAR |
| D. | volts |
| Answer» C. kVAR | |
| 52. |
While testing a capacitor with ohm-metre, if the capacitor shows charging, but the final resistance reading is appreciably less than normal, it can be concluded that the capacitor is |
| A. | short-circuited |
| B. | open circuited |
| C. | alright |
| D. | leaky |
| Answer» D. leaky | |
| 53. |
If a 6 (iF capacitor is charged to 200 V, the charge in coulombs will be |
| A. | 800 uC |
| B. | 900 uC |
| C. | 1200 uC |
| D. | 1600 uC |
| Answer» C. 1200 uC | |
| 54. |
Which capacitor will be physically smaller for the same ratings ? |
| A. | Ceramic capacitor |
| B. | Paper capacitor |
| C. | Both will be of equal size |
| D. | None of the above |
| Answer» A. Ceramic capacitor | |
| 55. |
What is the value of capacitance that must be connected in parallel with 50 pF condenser to make an equivalent capacitance of 150 pF ? |
| A. | 50 pF |
| B. | 100 pF |
| C. | 150 pF |
| D. | 200 pF |
| Answer» B. 100 pF | |
| 56. |
A mica capacitor and a ceramic capacitor both have the same physical dimensions. Which will have more value of capacitance ? |
| A. | Ceramic capacitor |
| B. | Mica capacitor |
| C. | Both will have identical value of capacitance |
| D. | It depends on applied voltage |
| Answer» A. Ceramic capacitor | |
| 57. |
Which of the following material has least value of dielectric constant ? |
| A. | Ceramics |
| B. | Oil |
| C. | Glass |
| D. | Paper |
| Answer» B. Oil | |
| 58. |
Which of the following capacitors will have the least value of breakdown voltage ? |
| A. | Mica |
| B. | Paper |
| C. | Ceramic |
| D. | Electrolytic |
| Answer» D. Electrolytic | |
| 59. |
Dielectric constant for mica is nearly |
| A. | 200 |
| B. | 100 |
| C. | 3 to 8 |
| D. | 1 to 2 |
| Answer» C. 3 to 8 | |
| 60. |
The value of dielectric constant for vacuum is taken as |
| A. | zero |
| B. | 1 |
| C. | 4 |
| D. | 10 |
| Answer» B. 1 | |
| 61. |
Which of the following capacitors is marked for polarity ? |
| A. | Air |
| B. | Paper |
| C. | Mica |
| D. | Electrolytic |
| Answer» D. Electrolytic | |
| 62. |
Which of the following capacitors can be used for temperature compensation ? |
| A. | Air capacitor |
| B. | Ceramic capacitor |
| C. | Paper capacitor |
| D. | None of the above |
| Answer» B. Ceramic capacitor | |
| 63. |
Which of the following statements is incorrect ? |
| A. | The thinner the dielectric, the more the capacitance and the lower the voltage breakdown rating for a capacitor . |
| B. | A six dot mica capacitor colour coded white, green, black, red and yellow has the capacitance value of 500 pF |
| C. | Capacitors in series provide less capacitance but a higher voltage breakdown rating for the combina¬tion |
| D. | A capacitor can store charge be¬cause it has a dielectric between two conductors |
| Answer» B. A six dot mica capacitor colour coded white, green, black, red and yellow has the capacitance value of 500 pF | |
| 64. |
Paper capacitors usually have a tolerance of |
| A. | ± 5% |
| B. | ± 10% |
| C. | ± 15% |
| D. | ± 20% |
| Answer» B. ± 10% | |
| 65. |
For closer tolerances which of the following capacitors is usually preferred ? |
| A. | Paper capacitor |
| B. | Mica capacitor |
| C. | Ceramic disc capacitor |
| D. | None of the above |
| Answer» B. Mica capacitor | |
| 66. |
The electrostatic force between two charges of one coulomb each and placed at a distance of 0.5 m will be |
| A. | 36 x 10fa |
| B. | 36 x 107 N |
| C. | 36 x 108 N |
| D. | 36 x 109 N |
| Answer» D. 36 x 109 N | |
| 67. |
The units of volume charge density are |
| A. | Coulomb/metre |
| B. | Coulomb/metre |
| C. | Coulomb/metre |
| D. | Coulomb/metre |
| Answer» C. Coulomb/metre | |
| 68. |
"The surface integral of the normal component of the electric displacement D over any closed surface equals the charge enclosed by the surface". The above statement is associated with |
| A. | Gauss's law |
| B. | Kirchhoff s law |
| C. | Faraday's law |
| D. | Lenz's law |
| Answer» A. Gauss's law | |
| 69. |
Dielectric strength of mica is |
| A. | 10 to 20 kV/mm |
| B. | 30 to 50 kV/mm |
| C. | 50 to 200 kV/mm |
| D. | 300 to 500 kV/mm |
| Answer» C. 50 to 200 kV/mm | |
| 70. |
The dielectric constant (relative permittivity) of glass is given by |
| A. | 0.1 to 0.4 |
| B. | 0.5 to 1.0 |
| C. | 2.0 to 4.0 |
| D. | 5 to 100 |
| Answer» D. 5 to 100 | |
| 71. |
capacitors are mainly used for radio frequency tuning. |
| A. | Paper |
| B. | Air |
| C. | Mica |
| D. | Electrolytic |
| Answer» B. Air | |
| 72. |
capacitors can be used only for D.C. |
| A. | Air |
| B. | Paper |
| C. | Mica |
| D. | Electrolytic |
| Answer» D. Electrolytic | |
| 73. |
capacitors are used in transistor circuits. |
| A. | Ceramic |
| B. | Paper |
| C. | Air |
| D. | Electrolytic |
| Answer» A. Ceramic | |
| 74. |
capacitors are used for audio frequency and radio frequency coupling and tuning. |
| A. | Air |
| B. | Mica |
| C. | Plastic film |
| D. | Ceramic |
| Answer» B. Mica | |
| 75. |
The inverse of capacitance is called |
| A. | reluctance |
| B. | conductance |
| C. | susceptance |
| D. | elastance |
| Answer» D. elastance | |
| 76. |
When the dielectric is homogeneous,the potential gradient is |
| A. | uniform |
| B. | non-uniform |
| C. | zero |
| D. | any of the above |
| Answer» A. uniform | |
| 77. |
The potential gradient across the material of low permittivity is than across the material of high permittivity. |
| A. | smaller |
| B. | greater |
| C. | both (a) and (b) |
| D. | none of the above |
| Answer» B. greater | |
| 78. |
________field is associated with the capacitor. |
| A. | Electric |
| B. | Magnetic |
| C. | Both (a) and (b) |
| D. | None of the above |
| Answer» A. Electric | |
| 79. |
A capacitor having capacitance of 5 uF is charged to a potential difference of 10,000 V. The energy stored in the capacitor is |
| A. | 50 joules |
| B. | 150 joules |
| C. | 200 joules |
| D. | 250 joules |
| Answer» D. 250 joules | |
| 80. |
A single core cable used on 33000 V has conductor diameter 10 mm and the in¬ternal diameter of sheath 25 mm. The maximum electrostatic stress in the cable is |
| A. | 62 x 105 V/m |
| B. | 72 x 105 V/m |
| C. | 82 x 105 V/m |
| D. | 92 x 105 V/m |
| Answer» B. 72 x 105 V/m | |
| 81. |
Two infinite parallel plates 10 mm apart have maintained between them a potential difference of 100 V. The acceleration of an electron placed between them is |
| A. | 0.56 x 1015 m/s2 |
| B. | 1.5 x 1015 m/s2 |
| C. | 1.6 x 1015 m/s2 |
| D. | 1.76 x 1015 m/s2 |
| Answer» D. 1.76 x 1015 m/s2 | |
| 82. |
The total deficiency or excess of electrons in a body is known as |
| A. | current |
| B. | voltage |
| C. | potential gradient |
| D. | charge |
| Answer» D. charge | |
| 83. |
The relative permittivity has the following units |
| A. | F/m |
| B. | m/F |
| C. | Wb/m |
| D. | no units |
| Answer» C. Wb/m | |
| 84. |
The phenomenon of an uncharged body getting charged merely by the nearness of a charged body is known as |
| A. | pholoelectric effect |
| B. | chemical effect |
| C. | magnetic effect |
| D. | induction |
| Answer» D. induction | |
| 85. |
A unit tube of flux is known as tube |
| A. | Newton |
| B. | Faraday |
| C. | Michale |
| D. | None of the above |
| Answer» B. Faraday | |
| 86. |
The number of Faraday tubes of flux passing through a surface in an electric field is called |
| A. | electric flux |
| B. | electric flux density |
| C. | magnetic flux density |
| D. | electric charge density |
| Answer» A. electric flux | |
| 87. |
The value of E within the field due to a point charge can be found with the help of |
| A. | Faraday's laws |
| B. | Kirchhoff s laws |
| C. | Coulomb's laws |
| D. | none of the above |
| Answer» C. Coulomb's laws | |
| 88. |
at a point may be defined as equal to the lines of force passing normally through a unit cross section at that point. |
| A. | Electric intensity |
| B. | Magnetic flux density |
| C. | Electric flux |
| D. | None of the above |
| Answer» A. Electric intensity | |
| 89. |
Electric intensity at any point in an electric field is equal to the at that point. |
| A. | electric flux |
| B. | magnetic flux density |
| C. | potential gradient |
| D. | none of the above |
| Answer» C. potential gradient | |
| 90. |
Electric displacement is a______quantity. |
| A. | scalar |
| B. | vector |
| C. | both of the above |
| D. | none of the above |
| Answer» B. vector | |
| 91. |
at a point is equal to the negative potential gradient at that point. |
| A. | Electric intensity |
| B. | Electric flux |
| C. | Magnetic flux |
| D. | Magnetic flux density |
| Answer» A. Electric intensity | |
| 92. |
The unit of dielectric strength is given by |
| A. | V/m |
| B. | V2/m |
| C. | m/V |
| D. | m/V2 |
| Answer» A. V/m | |
| 93. |
Dielectric strength ______ with increasing thickness |
| A. | increases |
| B. | decreases |
| C. | remains unaltered |
| D. | none of the above |
| Answer» B. decreases | |
| 94. |
The property of a capacitor to store electricity is called its |
| A. | capacitance |
| B. | charge |
| C. | energy |
| D. | none of the above |
| Answer» A. capacitance | |
| 95. |
is that property of a capacitor which delays any change of voltage across it. |
| A. | Inductance |
| B. | Capacitance |
| C. | Potential gradient |
| D. | None of the above |
| Answer» B. Capacitance | |
| 96. |
A capacitance of 100 fiF is connected in series with a resistance of 8000 £2. The time constant of the circuit is |
| A. | 0.2 s |
| B. | 0.4 s |
| C. | 0.6 s |
| D. | 0.8 s |
| Answer» D. 0.8 s | |
| 97. |
In a cable capacitor, voltage gradient ismaximum at the surface of the |
| A. | earth |
| B. | conduction |
| C. | sheath |
| D. | insulator |
| Answer» B. conduction | |
| 98. |
The time constant of an R-C circuit is defined as the time during which capacitor charging voltage actually rises to ______ percent of its______value. |
| A. | 37, initial |
| B. | 63.2, initial |
| C. | 63.2, final |
| D. | 37, final |
| Answer» C. 63.2, final | |
| 99. |
The time constant and R-C circuit may also be defined as the time during which the charging current falls to ______ percent of its initial maximum value, |
| A. | 37 |
| B. | 42 |
| C. | 63 |
| D. | 73 |
| Answer» A. 37 | |
| 100. |
A capacitor consists of two |
| A. | ceramic plates and one mica disc |
| B. | insulators separated by a dielectric |
| C. | silver-coated insulators |
| D. | conductors separated by an insulator |
| Answer» D. conductors separated by an insulator | |
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