# MCQ in Power Generators (Cells and Batteries) Part 2 | ECE Board Exam

(Last Updated On: May 3, 2019) This is the Multiples Choice Questions Part 2 of the Series in Power Generators, Sources, Principles and Applications as one of the Electronics Engineering topic. In Preparation for the ECE Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including but not limited to past Board Exam Questions in Electronics Engineering field, Electronics Books, Journals and other Electronics References.

### MCQ Topic Outline included in ECE Board Exam Syllabi

• MCQ in Cells and Batteries
• MCQ in Electric Generator
• MCQ in Electronic Power Supply
• MCQ in Voltage Regulation
• MCQ in Photovoltaic/Thermoelectric Generator
• MCQ in Distribution Transformer
• MCQ in Uninterrupted Power Supply (UPS)
• MCQ in Float-Battery System
• MCQ in Converters
• MCQ in Inverters

### Continue Practice Exam Test Questions Part 2 of the Series

Choose the letter of the best answer in each questions.

51. The voltage of the bus bar to which several alternators are paralleled may be raised by simultaneously ____________ of all alternators

A. increasing field excitation

B. decreasing field excitation

C. increasing input to prime movers

D. decreasing input to prime movers

Solution:

52. The rating of an alternator is expressed in

A. kW

B. kVA

C. HP

D. KVAR

Solution:

53. Cumulatively compounded motors are used in applications where ____________ is required

A. variable speed

B. poor speed regulation

C. sudden heavy loads for a short duration

D. constant speed

Solution:

54. Which motor never use belt connected loads?

A. Series

B. Commulatively compounded

C. Shunt

D. Differentially compounded

Solution:

55. A standalone solar power system

A. relies on the electric utility at night

B. uses solar panels and batteries

C. requires the use of dry cells

D. need a full wave rectifier

Solution:

56. A transformer will have zero efficiency at

Solution:

57. The efficiency of a transformer will be at maximum when

A. leakage reactance of the two windings are equal

B. resistance of the two windings are equal

C. copper loss is equal to constant loss

D. copper loss is zero

Solution:

58. The armature winding of a dc Machine is ____________ winding

A. an open circuit

B. a closed circuit

C. partly open circuit and partly closed circuit

D. lap

Solution:

59. The speed at which a 6 pole alternator should be drive to generate 50 cycles per second is

A. 1500 rpm

B. 500 rpm

C. 1000 rpm

D. 1200 rpm

Solution:

60. A 12 V battery is rated at 48 ah. If it must deliver an average of 2.0 A, how long will the battery last before it needs recharging

A. 48 hrs

B. 4 hrs

C. 96 hrs

D. 24 hrs

Solution:

61. Connecting batteries of equal voltage in parallel

A. multiplies the voltage available

B. increases the internal resistance

C. reduces the power available

D. multiplies the current available

Solution:

62. A storage battery in which the electrodes are grids of lead containing lead oxides that changes in composition during charging and discharging and the electrolyte is dilute sulfuric acid

A. Leclanche battery

D. Faure storage battery

Solution:

63. The common dry cell, which is a primary cell having a carbon positive electrode and a zinc negative electrode in an electrolyte of sal ammoniac and a depolarizer

A. Leclanche cell

B. Faure storage cell

D. Lithium cell

Solution:

64. The maximum flux produced in the core of a transformer is

A. directly proportional to supply frequency

B. inversely proportional to supply frequency

C. inversely proportional to primary voltage

D. inversely proportional to secondary voltage

Solution:

65. A transformer is so designed that primary and secondary windings have

A. loose magnetic coupling

B. tight magnetic coupling

C. critical magnetic coupling

D. good electric coupling

Solution:

66. Four carbon zinc cell in series will provide about

A. 2 Vdc

B. 6 Vdc

C. 9 Vdc

D. 8 Vdc

Solution:

67. What refers to a method in which the charger and the battery are always connected to each other for supplying current to the load

A. Continuous charging

B. Float charging

C. Infinite charging

D. On line charging

Solution:

68. A series motor designed to operate on dc or ac

A. Shunt motor

B. Series motor

C. Universal motor

D. Compound motor

Solution:

69. Combination of ac motor, dc generator, and exciter to provide adjustable voltage dc power to a dc motor.

A. Ward-Leonard system

B. Half wave SCR adjustable voltage supply

C. Compound motor

D. Universal motor

Solution:

70. A motor takes a large current at starting because

A. the armature resistance is high

B. back emf is low

C. back emf is high

D. shunt field is producing weak field

Solution:

71. A series motor will over speed when

B. the armature circuit is open

C. the field id opened

Solution:

72. When the load on an alternator is increased, the terminal voltage increases if the load power factor is

A. unity

C. lagging

D. zero

Solution:

73. The efficiency of the turbo-alternator _____________ with increase in speed

A. decreases

B. remains the same

C. increases

D. becomes 100%

Solution:

74. What is the output of a lead acid cell?

A. 2.1 V

B. 1.5 V

C. 1.35 V

D. 1.25 V

Solution:

75. One of the following is a false statement

A. storage cell has a reversible chemical reaction

B. carbon zinc cell has unlimited shelf life

C. lead acid cell is rechargeable

D. primary cell is not rechargeable

Solution:

76. In an alternator, the effect of armature reaction is minimum at power factor of

A. 0.866 lagging

B. 0.5 lagging

D. Unity

Solution:

77. For given number of poles (2) and armature conductors, a lap winding will carry ___________ a wave winding

A. more current than

B. same current as

C. less current than

D. half the current than

Solution:

78. An 8 pole duplex lap winding will have ____________ parallel paths

A. 8

B. 32

C. 4

D. 16

Solution:

79. To increase the voltage output, cells are connected in

A. parallel

B. series-parallel

C. parallel-series

D. series

Solution:

80. To increase current capacity, cells are connected in

A. parallel

B. series

C. series- parallel

D. parallel- series

Solution:

81. Two things which are same for primary and secondary of transformer are

A. ampere turns and voltage per turn

B. resistance and leakage reactance

C. current and inducted voltage

D. number of turns and power

Solution:

82. A transformer operates poorly at very low frequencies because

A. permeability of core is increased

B. magnetizing current is abnormally high

C. primary reactance is too much

D. permeability core is reduced

Solution:

83. In an auto transformer, the primary and secondary are ___________ coupled

A. only magnetically

B. magnetically as well as electrically

C. only electrically

D. directly

Solution:

84. A storage battery in which the plates consist if lead antimony supporting grids covered with a lead oxide paste immersed in weak sulfuric acid

A. Leclanche cell

B. primary battery

C. secondary battery

D. Faure storage battery

Solution:

85. Which of the following is a dry storage cell?

A. Leclanche cell

B. Edison cell

C. Mercury cell

Solution:

86. The field structure of a dc machine uses

A. Salient pole arrangement

B. Non salient pole arrangement

C. Silicon steel

D. Cast steel

Solution:

87. Small Dc machines generally have __________ poles

A. 4

B. 2

C. 6

D. 8

Solution:

88. The armature of a dc machine is laminated in order to reduce

A. Eddy current loss

B. Copper loss

C. Hysteresis loss

D. Frictional loss

Solution:

89. To produce an output of 7.5v, how many carbon zinc cells are connected in series?

A. 4

B. 5

C. 6

D. 3

Solution:

90. The demand for a large increase in torque of a dc series motor is met by a

A. large decrease in current

B. large increase in speed

C. large decrease in speed

D. small decrease in speed

Solution:

91. As the load increases a, ____________ motor will speed up

A. series

B. commutatively compounded

C. shunt

D. differentially compounded

Solution:

92. The flux in the core of a single phase transformer is

A. purely alternating one

B. purely rotating one

C. partly alternating and partly rotating

D. constant

Solution:

93. When the primary of a transformer is connected to a dc supply

A. a primary draw small current

B. primary leakage reactance is increased

C. core losses are increased

D. primary may burned out

Solution:

94. a constant voltage source has

A. High internal resistance

B. minimum efficiency

C. minimum current capacity

D. low internal resistance

Solution:

95. If the excitation of an alternator operating in parallel with other alternators is increased above the normal value excitation of excitation its

A. power factor becomes more lagging

B. output current decreases

C. power factor becomes more leading

D. output kw decreases

Solution:

96. This synchronous reactance of an alternator is generally ____________ armature resistance

A. 5 times smaller than

B. 10 – 100 times greater than

C. 5 times greater than

D. 10 times smaller than

Solution:

97. DC series motors are used in those applications where ____________ required

A. high starting torque

C. constant speed

D. variable speed

Solution:

98. A dc motor is still used in industrial applications because it

A. is cheap

B. provides fine speed control

C. is simple in construction

D. has no replacement

Solution:

99. The stator of n alternator is wound for ____________ on the rotor

A. a more number of poles than

B. the same number of poles as

C. less number of poles than

D. twice the number of poles

Solution:

100. Why are carbon brushes preferable compared to copper brushes?

A. they have longer life

B. they have lower resistance

C. they are cheaper

D. they reduce sparking

Solution:

### Questions and Answers in Power Generators, Sources, Principles, Applications

Following is the list of practice exam test questions in this brand new series:

MCQ in in Power Generators, Sources, Principles, Applications
PART 1: MCQs from Number 1 – 50                        Answer key: PART 1
PART 2: MCQs from Number 51 – 100                   Answer key: PART 2
PART 3: MCQs from Number 101 – 150                 Answer key: PART 3
PART 4: MCQs from Number 151 – 200                 Answer key: PART 4
PART 5: MCQs from Number 201 – 250                 Answer key: included
PART 6: MCQs from Number 251 – 300                 Answer key: included
PART 7: MCQs from Number 301 – 350                 Answer key: included
PART 8: MCQs from Number 351 – 400                 Answer key: included
PART 9: MCQs from Number 401 – 450                 Answer key: included
PART 10: MCQs from Number 451 – 500                 Answer key: included