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This section includes 198 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.
51. |
Weston standard cell at 20°C has voltage of ____ volts. |
A. | 0.8 |
B. | 0.9 |
C. | 1.0187 |
D. | 1.5 |
Answer» D. 1.5 | |
52. |
Sulphated cells are indicated by |
A. | the loss of capacity of the cell |
B. | the decrease of the specific gravity |
C. | the low voltage of the cell on discharge |
D. | all above conditions |
Answer» E. | |
53. |
If a lead-acid cell is discharged below 1.8 V the following will happen. |
A. | Capacity of cell will reduce |
B. | Sulphation of plates will occur |
C. | Internal resistance will increase |
D. | All above will occur |
Answer» E. | |
54. |
The substances which combine together to store electrical energy during the charge are called ______ materials |
A. | active |
B. | passive |
C. | inert |
D. | dielectric |
Answer» B. passive | |
55. |
The common impurity in the electrolyte of lead-acid battery is |
A. | chlorine |
B. | dust particles |
C. | lead crystals |
D. | iron |
Answer» E. | |
56. |
In alkaline cell the electrolyte is |
A. | dilute sulphuric acid |
B. | concentrated sulphuric acid |
C. | NaOH |
D. | kOH |
Answer» E. | |
57. |
Dry cell is modification of |
A. | Deniell cell |
B. | Leclanche cell |
C. | Lead-acid cell |
D. | Edison cell |
Answer» C. Lead-acid cell | |
58. |
As compared to a lead-acid cell, the efficiency of a nickel-iron cell is less due to its |
A. | compactness |
B. | lower e.m.f. |
C. | small quantity of electrolyte used |
D. | higher internal resistance |
Answer» E. | |
59. |
During the idle period of the battery, strong electrolyte tends to change the active material of the cell into |
A. | Pb02 |
B. | PbSC-4 |
C. | PbO |
D. | Pb |
Answer» C. PbO | |
60. |
Charging a sulphated battery at high rate results in |
A. | boiling of electrolyte due to gassing |
B. | warping of plates |
C. | damage to separators, cell caps covers and battery case due to excessive temperature |
D. | all above |
Answer» E. | |
61. |
Five 2 V cells are connected in parallel. The output voltage is |
A. | 1 V |
B. | 1.5 V |
C. | 1.75 V |
D. | 2 V |
Answer» E. | |
62. |
Negative plate of an Edison cell is made of |
A. | copper |
B. | lead |
C. | iron |
D. | silver oxide |
Answer» D. silver oxide | |
63. |
Following will happen if battery charging rate is too high |
A. | excessive gassing will occur |
B. | temperature rise will occur |
C. | bulging and buckling of plates will occur |
D. | all above will occur |
Answer» E. | |
64. |
Mercury cell has which of the following characteristics? |
A. | Flat discharge current-voltage curve |
B. | High power to weight ratio |
C. | Comparatively longer shelf life under adverse conditions of high temperature and humidity |
D. | All of the above |
Answer» E. | |
65. |
As compared to constant-current system, the constant-voltage system of charging a lead acid cell has the advantage of |
A. | reducing time of charging |
B. | increasing cell capacity |
C. | both (A) and (B) |
D. | avoiding excessive gassing |
Answer» D. avoiding excessive gassing | |
66. |
_______ of electrolyte indicates the state of charge of the battery |
A. | colour |
B. | mass |
C. | viscosity |
D. | specific gravity |
Answer» E. | |
67. |
Excessive charging a battery tends to |
A. | produce gassing |
B. | increase the internal resistance of the battery |
C. | to corrode the positive plates into lead peroxide thereby weakening them physically |
D. | bring about all above changes |
Answer» E. | |
68. |
The active material of the positive plates of silver-zinc batteries is |
A. | silver oxide |
B. | lead oxide |
C. | lead |
D. | zinc powder |
Answer» B. lead oxide | |
69. |
Batteries are charged by |
A. | rectifiers |
B. | engine generator sets |
C. | motor generator sets |
D. | any one of the above methods |
Answer» E. | |
70. |
On overcharging a battery |
A. | It will bring about chemical change in active materials |
B. | It will increase the capacity of the battery |
C. | It will raise the specific gravity of the electrolyte |
D. | None of the above will occur |
Answer» E. | |
71. |
Cells are connected in parallel to |
A. | Increase the efficiency |
B. | Increase the current capacity |
C. | Increase the voltage output |
D. | Increase the internal resistance |
Answer» C. Increase the voltage output | |
72. |
Electrolyte used in a lead-acid cell is |
A. | NaOH |
B. | only H₂SO₄ |
C. | only water |
D. | dilute H₂SO₄ |
Answer» E. | |
73. |
The ratio of ampere-hour efficiency to watt-hour efficiency of a lead-acid cell is |
A. | just one |
B. | always greater than one |
C. | always less than one |
D. | none of the above |
Answer» C. always less than one | |
74. |
While preparing electrolyte for a lead-acid battery |
A. | water is poured into acid |
B. | acid is poured into water |
C. | anyone of the two can be added to other chemical |
D. | none of the above |
Answer» C. anyone of the two can be added to other chemical | |
75. |
During charging the specific gravity of the electrolyte of a lead-acid battery |
A. | increases |
B. | decreases |
C. | remains the same |
D. | becomes zero |
Answer» B. decreases | |
76. |
Electrolyte used in a lead-acid cell is%! |
A. | NaOH |
B. | only H‚ÇÇSO‚ÇÑ |
C. | only water |
D. | dilute H‚ÇÇSO‚ÇÑ |
Answer» E. | |
77. |
The e.m.f. of an Edison cell, when fully charged, is nearly%! |
A. | 1.4 V |
B. | 1 V |
C. | 0.9 V |
D. | 0.8 V |
Answer» B. 1 V | |
78. |
A battery of 6 cells will show a drop of _____ volts from fully charged state to fully discharged state.%! |
A. | 1.0 |
B. | 1.5 |
C. | 2.4 |
D. | 2.9 |
Answer» D. 2.9 | |
79. |
A dead storage battery can be revived by%! |
A. | adding distilled water |
B. | adding so-called battery restorer |
C. | a dose of H‚ÇÇSO‚ÇÑ |
D. | none of the above |
Answer» E. | |
80. |
Over charging%! |
A. | produces excessive gassing |
B. | loosens the active material |
C. | increases the temperature resulting in buckling of plates |
D. | all above |
Answer» E. | |
81. |
The specific gravity of electrolyte is measured by%! |
A. | manometer |
B. | a mechanical gauge |
C. | hydrometer |
D. | psychrometer |
Answer» D. psychrometer | |
82. |
Cells are connected in series in order to%! |
A. | increase the voltage rating |
B. | increase the current rating |
C. | increase the life of the cells |
D. | none of the above |
Answer» B. increase the current rating | |
83. |
Undercharging%! |
A. | Reduces specific gravity of the electrolyte |
B. | Increases specific gravity of the electrolyte |
C. | Produces excessive gassing |
D. | Increases the temperature |
Answer» B. Increases specific gravity of the electrolyte | |
84. |
Local action in a battery is indicated by%! |
A. | excessive gassing under load conditions |
B. | excessive drop in the specific gravity of electrolyte even when the cell is on open circuit |
C. | both (A) and (B) |
D. | none of the above |
Answer» E. | |
85. |
*$_Sulphated cells are indicated by? |
A. | the loss of capacity of the cell |
B. | the decrease of the specific gravity |
C. | the low voltage of the cell on discharge |
D. | all above conditions |
Answer» E. | |
86. |
*$_Electrolyte used in a lead-acid cell is? |
A. | NaOH |
B. | only H‚ÇÇSO‚ÇÑ |
C. | only water |
D. | dilute H‚ÇÇSO‚ÇÑ |
Answer» E. | |
87. |
*/*_The e.m.f. of an Edison cell, when fully charged, is nearly? |
A. | 1.4 V |
B. | 1 V |
C. | 0.9 V |
D. | 0.8 V |
Answer» B. 1 V | |
88. |
*/*_Negative plate of an Edison cell is made of? |
A. | copper |
B. | lead |
C. | iron |
D. | silver oxide |
Answer» D. silver oxide | |
89. |
*/*_During the idle period of the battery, strong electrolyte tends to change the active material of the cell into? |
A. | Pb02 |
B. | PbSC-4 |
C. | PbO |
D. | Pb |
Answer» C. PbO | |
90. |
*/*_As compared to constant-current system, the constant-voltage system of charging a lead acid cell has the advantage of? |
A. | reducing time of charging |
B. | increasing cell capacity |
C. | both (A) and (B) |
D. | avoiding excessive gassing |
Answer» D. avoiding excessive gassing | |
91. |
*/*_The active material of the positive plates of silver-zinc batteries is? |
A. | silver oxide |
B. | lead oxide |
C. | lead |
D. | zinc powder |
Answer» B. lead oxide | |
92. |
*/*_The watt-hour efficiency of a lead-acid cell varies between? |
A. | 25 to 35% |
B. | 40 to 60% |
C. | 70 to 80% |
D. | 90 to 95% |
Answer» D. 90 to 95% | |
93. |
*/*_In alkaline cell the electrolyte is? |
A. | dilute sulphuric acid |
B. | concentrated sulphuric acid |
C. | NaOH |
D. | kOH |
Answer» E. | |
94. |
*/*_The ampere-hour efficiency of a leadacid cell is normally between? |
A. | 20 to 30% |
B. | 40 to 50% |
C. | 60 to 70% |
D. | 90 to 95% |
Answer» E. | |
95. |
*/*_Chargmg of sulphated battery produces ____ heat.? |
A. | no |
B. | very little |
C. | less |
D. | more |
Answer» E. | |
96. |
*/*_Which among the following constitutes the major load for an automobile battery ?? |
A. | Brake light |
B. | Self starter |
C. | Parking lights |
D. | Spark plugs |
Answer» C. Parking lights | |
97. |
*/*_48 ampere-hour capacity would deliver a current of? |
A. | 48 amperes for 1 hour |
B. | 24 amperes for 2 hours |
C. | 8 amperes for 6 hours |
D. | 6 amperes for 8 hours |
Answer» E. | |
98. |
*/*_The active materials on the positive and negative plates of a fully charged lead-acid battery are? |
A. | lead and lead peroxide |
B. | lead sulphate and lead |
C. | lead peroxide and lead |
D. | none of the above |
Answer» D. none of the above | |
99. |
*/*_The ratio of ampere-hour efficiency to watt-hour efficiency of a lead-acid cell is? |
A. | just one |
B. | always greater than one |
C. | always less than one |
D. | none of the above |
Answer» C. always less than one | |
100. |
%_In constant-current charging method, the supply voltage from discharged to fully charged condition_% |
A. | decreases |
B. | increases |
C. | remains constant |
D. | none of the above |
Answer» C. remains constant | |