Quiz  /  Electrolysis and storage of Batteries Electrical Engineering MCQ Questions and Answers PDF

  • 1. 
    “The mass of an ion liberated at an electrode is directly proportional to the quantity of electricity”. The above statement is associated with

  • Newton’s law
  • Faraday’s law of electromagnetic
  • Faraday’s law of electrolysis
  • Gauss’s law

  • 2. 
    During the charging of a lead-acid cell

  • its voltage increases
  • it gives out energy
  • its cathode becomes dark chocolate brown in colour
  • specific gravity of H2SO4 decreases

  • 3. 
    The capacity of a lead-acid cell does not depend on its

  • temperature
  • rate of charge
  • rate of discharge
  • quantity of active material

  • 4. 
    During charging the specific gravity of the electrolyte of a lead-acid battery

  • increases
  • decreases
  • remains the same
  • becomes zero

  • 5. 
    The active materials on the positive and negative plates of a fully charged lead-acid battery are

  • lead and lead peroxide
  • lead sulphate and lead
  • lead peroxide and lead
  • none of the above

  • 6. 
    When a lead-acid battery is in fully charged condition, the color of its positive plate is

  • dark grey
  • brown
  • dark brown
  • none of above

  • 7. 
    The ratio of ampere-hour efficiency to watt-hour efficiency of a lead-acid cell is

  • just one
  • always greater than one
  • always less than one
  • none of the above.

  • 8. 
    The best indication about the state of charge on a lead-acid battery is given by

  • output voltage
  • temperature of electrolyte
  • specific gravity of electrolyte
  • none of the above

  • 9. 
    The storage battery generally used in electric power station is

  • nickel-cadmium battery
  • zinc-carbon battery
  • lead-acid battery
  • none of the above

  • 10. 
    The output voltage of a charger is

  • less than the battery voltage
  • higher than the battery voltage
  • the same as the battery voltage
  • none of the above

  • 11. 
    The capacity of a battery is expressed in terms of

  • current rating
  • voltage rating
  • ampere-hour rating
  • none of the above

  • 12. 
    During the charging and discharging of a nickel-iron cell

  • corrosive fumes are produced
  • water is neither formed nor absorbed
  • nickel hydroxide remains unsplit
  • its e.m.f. remains constant

  • 13. 
    As compared to constant-current system, the constant-voltage system of charging a lead acid cell has the advantage of

  • reducing time of charging
  • increasing cell capacity
  • both (a) and (b)
  • avoiding excessive gassing

  • 14. 
    As compared to a lead-acid cell, the efficiency of a nickel-iron cell is less due to its

  • compactness
  • lower e.m.f.
  • small quantity of electrolyte used
  • higher internal resistance

  • 15. 
    Trickle charging of a storage battery helps to

  • maintain proper electrolyte level
  • increase its reserve capacity
  • prevent sulphation
  • keep it fresh and fully charged

  • 16. 
    Those substances of the cell which take active part in chemical combination and hence produce electricity during charging or discharging are known as______materials.

  • passive
  • active
  • redundant
  • inert

  • 17. 
    In a lead-acid cell dilute sulfuric acid (electrolyte) approximately comprises the following

  • one part H2O, three parts H2SO4
  • two parts H2O, two parts H2SO4
  • three parts H2O, one part H2SO4
  • all H2S04

  • 18. 
    It is noticed that during discharging the following does not happen

  • both anode and cathode become PbS04
  • specific gravity of H2SO4 decreases
  • voltage of the cell decreases
  • the cell absorbs energy

  • 19. 
    The ampere-hour efficiency of a leadacid cell is normally between

  • 20 to 30%
  • 40 to 50%
  • 60 to 70%
  • 90 to 95%

  • 20. 
    The watt-hour efficiency of a lead-acid cell varies between

  • 25 to 35%
  • 40 to 60%
  • 70 to 80%
  • 90 to 95%

  • 21. 
    The capacity of a lead-acid cell is measured in

  • amperes
  • ampere-hours
  • watts
  • watt-hours

  • 22. 
    The capacity of a lead-acid cell depends on

  • rate of discharge
  • temperature
  • density of electrolyte
  • quantity of active materials
  • all above

  • 23. 
    When the lead-acid cell is fully charged, the electrolyte assumes _____ appearance

  • dull
  • reddish
  • bright
  • milky

  • 24. 
    The e.m.f. of an Edison cell, when fully charged, is nearly

  • 1.4 V
  • 1 V
  • 0.9 V
  • 0.8 V

  • 25. 
    The internal resistance of an alkali cell is nearly _____ times that of the lead-acid cell.

  • two
  • three
  • four
  • five

  • 26. 
    The average charging voltage for alkali cell is about

  • 1 V
  • 1.2 V
  • 1.7 V
  • 2.1 V

  • 27. 
    On the average the ampere-hour efficiency of an Edison cell is about

  • 40%
  • 60%
  • 70%
  • 80%

  • 28. 
    The active material of the positive plates of silver-zinc batteries is

  • silver oxide
  • lead oxide
  • lead
  • zinc powder

  • 29. 
    Lead-acid cell has a life of nearly charges and discharges

  • 500
  • 700
  • 1000
  • 1250

  • 30. 
    Life of the Edison cell is at least

  • five years
  • seven years
  • eight years
  • ten years

  • 31. 
    The internal resistance of a lead-acid cell is that of Edison cell

  • less than
  • more than
  • equal to
  • none of the above

  • 32. 
    Electrolyte used in an Edison cell is

  • NaOH
  • KOH
  • HC1
  • HN03

  • 33. 
    Electrolyte used in a lead-acid cell is

  • NaOH
  • onlyH2S04
  • only water
  • dilute H2SO4

  • 34. 
    Negative plate of an Edison cell is made of

  • copper
  • lead
  • iron
  • silver oxide

  • 35. 
    The open circuit voltage of any storage cell depends wholly upon

  • its chemical constituents
  • on the strength of its electrolyte
  • its temperature
  • all above

  • 36. 
    When the specific gravity of the electrolyte of a lead-acid cell is reduced to 1.1 to 1.15 the cell is in

  • charged state
  • discharged state
  • both (a) and (b)
  • active state

  • 37. 
    In ______ system the charging current is intermittently controlled at either a maximum or minimum value

  • two rate charge control
  • trickle charge
  • floating charge
  • an equalizing charge

  • 38. 
    Over charging

  • produces excessive gassing
  • loosens the active material
  • increases the temperature resulting in buckling of plates
  • all above

  • 39. 
    Undercharging

  • reduces specific gravity of the electrolyte
  • increases specific gravity of the electrolyte
  • produces excessive gassing
  • increases the temperature

  • 40. 
    Internal short circuits are caused by

  • breakdown of one or more separators
  • excess accumulation of sediment at the bottom of the cell
  • both (a) and (b)
  • none of the above

  • 41. 
    The effect of sulphation is that the internal resistance

  • increases
  • decreases
  • remains same
  • none of the above

  • 42. 
    Excessive formation of lead sulphate on the surface of the plates happens because of

  • allowing a battery to stand in discharged condition for a long time
  • topping up with electrolyte
  • persistent undercharging
  • low level of electrolyte
  • all above

  • 43. 
    The substances which combine together to store electrical energy during the charge are called ______ materials

  • active
  • passive
  • inert
  • dielectric

  • 44. 
    In a lead-acid cell, lead is called as

  • positive active material
  • negative active material
  • passive material
  • none of the above

  • 45. 
    The lead-acid cell should never be discharged beyond

  • 1.8 V
  • 1.9 V
  • 2 V
  • 2.1 V

  • 46. 
    On overcharging a battery

  • it will bring about chemical change in active materials
  • it will increase the capacity of the battery
  • it will raise the specific gravity of the electrolyte
  • none of the above will occur

  • 47. 
    Each cell has a vent cap

  • to allow gases out when the cell is on charge
  • to add water to the cell if needed
  • to check the level of electrolyte
  • to do all above functions

  • 48. 
    Following will occur if level of electrolyte falls below plates

  • capacity of the cell is reduced
  • life of the cell is reduced
  • open plates are converted to lead sulphate
  • all above

  • 49. 
    In constant voltage charging method, the charging current from discharged to fully charged condition

  • decreases
  • increases
  • remains constant
  • none of the above

  • 50. 
    48 ampere-hour capacity would deliver a current of

  • 48 amperes for 1 hour
  • 24 amperes for 2 hours
  • 8 amperes for 6 hours
  • 6 amperes for 8 hours

  • 51. 
    In constant-current charging method, the supply voltage from discharged to fully charged condition

  • decreases
  • increases
  • remains constant
  • none of the above

  • 52. 
    Battery charging equipment is generally installed

  • in well ventilated location
  • in clean and dry place
  • as near as practical to the battery being charged
  • in location having all above features

  • 53. 
    Following will happen if the specific gravity of electrolyte becomes more than 1.23.

  • Loss of capacity
  • Loss of life
  • Corrosion of the grids of the plate
  • All above

  • 54. 
    Batteries are charged by

  • rectifiers
  • engine generator sets
  • motor generator sets
  • any one of the above methods

  • 55. 
    Cell short circuit results in

  • low sp. gravity electrolyte
  • abnormal high temperature
  • reduced gassing on charge
  • all above

  • 56. 
    Internal resistance of a cell is reduced by

  • using vent plug to permit gas formed during discharge
  • increasing the plate area
  • putting plates very close together
  • all above methods

  • 57. 
    Capacity of dry cells is

  • more when it is supplying current for intermittent periods
  • more when it is supplying current for continuous periods
  • unaffected by the type of discharge
  • none of the above

  • 58. 
    Battery container should be acid resistance, therefore it is made up of

  • glass
  • plastic
  • wood
  • all above

  • 59. 
    In a lead-acid cell, if the specific gravity of sulphuric acid is 1.8, it will require following ratio of acid to water to get mixture of specific gravity of 1.3

  • 6 parts of acid to 4 parts of water
  • 4 parts of acid to 4 parts of water
  • 4 parts of acid to 6 parts of water
  • 4 parts of acid to 8 parts of water

  • 60. 
    Local action in a battery is indicated by

  • excessive gassing under load conditions
  • excessive drop in the specific gravity of electrolyte even when the cell is on open circuit
  • both (a) and (b)
  • none of the above

  • 61. 
    Following will happen if battery charging rate is too high

  • excessive gassing will occur
  • temperature rise will occur
  • bulging and buckling of plates will occur
  • all above will occur

  • 62. 
    Internal resistance of a cell is due to

  • resistance of electrolyte
  • electrode resistance
  • surface contact resistance between electrode and electrolyte
  • all above

  • 63. 
    If a battery is wrongly connected on charge following will happen

  • current delivered by the battery will be high
  • current drawing will be nil
  • current drawing will be very small
  • current drawing will be very high

  • 64. 
    In order that a hydrometer may float vertically in electrolyte its C.G. should be

  • lowered
  • raised
  • undisturbed
  • displaced sideways

  • 65. 
    If a lead-acid cell is discharged below 1.8 V the following will happen.

  • Capacity of cell will reduce
  • Sulphation of plates will occur
  • Internal resistance will increase
  • All above will occur

  • 66. 
    Life of the batteries is in the following ascending order.

  • Lead-acid cell, Edison cell, Nickel cadmium cell
  • Lead-acid cell, Nickel-cadmium cell, Edison cell
  • Edison cell, Nickel-cadmium cell, lead-acid cell
  • Nickel-cadmium cell, Edison cell, lead-acid cell

  • 67. 
    Persons preparing electrolyte should wear

  • goggles or other face shield
  • rubber
  • rubber boots and gloves
  • all above safety devices

  • 68. 
    Excessive charging a battery tends to

  • produce gassing
  • increase the internal resistance of the battery
  • to corrode the positive plates into lead peroxide thereby weakening them physically
  • bring about all above changes

  • 69. 
    The current flow through electrolyte is due to the movement of

  • ions
  • holes
  • electrons
  • none of the above

  • 70. 
    Level of electrolyte in a cell should be _____ the level of plates

  • below
  • equal to
  • above
  • none of the above

  • 71. 
    During discharge, the active material of both the positive and negative plates is changed to

  • Pb
  • Pb02
  • PbO
  • PbS04

  • 72. 
    _____ of electrolyte indicates the state of charge of the battery

  • colour
  • mass
  • viscosity
  • specific gravity

  • 73. 
    The following indicate that battery on charge has attained full charge

  • colour of electrode
  • gassing
  • specific gravity
  • all above

  • 74. 
    Dry cell is modification of

  • Deniell cell
  • Leclanche cell
  • Lead-acid cell
  • Edison cell

  • 75. 
    Capacity of a battery.is expressed in

  • Ah
  • Vh
  • Wh
  • kWh

  • 76. 
    In alkaline cell the electrolyte is

  • dilute sulphuric acid
  • concentrated sulphuric acid
  • NaOH
  • KOH

  • 77. 
    Self charge of a Ni-Fe cell is _____ Edison cell.

  • equal to
  • less than
  • more than
  • much more than

  • 78. 
    Ampere hour capacity of an industrial battery is based on ____ hours discharge rate.

  • 8
  • 12
  • 16
  • 24

  • 79. 
    The body of Edison cell is made of

  • bakelite
  • rubber
  • nickel plated steel
  • aluminium

  • 80. 
    Specific gravity of electrolyte in Edison cell is

  • 0.8
  • 0.95
  • 1.1
  • 1.21

  • 81. 
    All the electrical connections between the battery and vehicle should be by

  • thin aluminium wires
  • thin copper wires
  • rigid cables
  • flexible cables

  • 82. 
    A battery of 6 cells will show a drop of _____ volts from fully charged state to fully discharged state.

  • 1.0
  • 1.5
  • 2.4
  • 2.9

  • 83. 
    Chargmg of sulphated battery produces ____ heat.

  • no
  • very little
  • less
  • more

  • 84. 
    Hydrogen evolved during charging produces explosive mixture when it is more than

  • 2%
  • 4%
  • 6%
  • 8%

  • 85. 
    Weston standard cell at 20°C has voltage of ____ volts.

  • 0.8
  • 0.9
  • 1.0187
  • 1.5

  • 86. 
    Extent of corrosion in the underground metal work depends upon

  • amount of moisture
  • type of metals
  • type of soil chemicals
  • all above factors

  • 87. 
    Charging a sulphated battery at high rate results in

  • boiling of electrolyte due to gassing
  • warping of plates
  • damage to separators, cell caps covers and battery case due to excessive temperature
  • all above

  • 88. 
    Short circuiting of a cell may be caused

  • buckling of plates
  • faulty separators
  • lead particles forming circuit between positive and negative plates
  • excessive accumulation of sediment
  • any one of above

  • 89. 
    . In a battery cover is placed over the element and sealed to the top of the battery container. This is done

  • to reduce evaporation of water from electrolyte
  • to exclude dirt and foreign matter from the electrolyte
  • to discharge both of the above functions
  • to discharge none of the above functions

  • 90. 
    . For a cell to work, which of the following condition(s) become necessary ?

  • Two electrodes of different meta’s should be inserted in the electrolyte, not touching each other
  • Electrolyte must chemically react with one of the electrodes
  • Electrolyte liquid or paste should be conducting
  • All above three conditions are necessary

  • 91. 
    . Which of the following primary cells has the lowest voltage ?

  • Lithium
  • Zinc-chloride
  • Mercury
  • Carbon-zinc

  • 92. 
    . Which of the following battery is used for air-craft ?

  • Lead-acid battery
  • Nickel-iron battery
  • Dry cell battery
  • Silver oxide battery

  • 93. 
    . Which of the following cell has a. reversible chemical reaction ?

  • Lead-acid
  • Mercury oxide
  • Carbon-zinc
  • Silver-oxide

  • 94. 
    . Which of the following is incorrect ?

  • A storage cell has a reversible chemical reaction
  • A lead-acid cell can be recharged
  • A carbon-zinc cell has unlimited shelf life
  • A primary cell has an irreversible chemical reaction

  • 95. 
    . Under normal charging rate, the charging current should be

  • 10% of capacity
  • 20% of capacity
  • 30% of capacity
  • 40% of capacity

  • 96. 
    . When two batteries are connected in parallel, it should be ensured that

  • they have same e.m.f.
  • they have same make
  • they have same ampere-hour capacity
  • they have identical internal resistance

  • 97. 
    . A typical output of a solar cell is

  • 0.1V
  • 0.26 V
  • 1.1 V
  • 2 V

  • 98. 
    . Petroleum jelly is applied to the electrical connections to the lead-acid battery

  • prevent local heating
  • prevent short-circuiting
  • reduce path resistance
  • prevent corrosion

  • 99. 
    . When the load resistance equals the generator resistance which of the following will be maximum ?

  • Current
  • Efficiency of the circuit
  • Power in the load resistance
  • Voltage across the load resistance

  • 100. 
    . The common impurity in the electrolyte of lead-acid battery is

  • chlorine
  • dust particles
  • lead crystals
  • iron

  • 101. 
    . In a lead-acid battery the energy is stored in the form of

  • charged ions
  • chemical energy
  • electrostatic energy
  • electromagnetic energy

  • 102. 
    . Which among the following constitutes the major load for an automobile battery ?

  • Brake light
  • Self starter
  • Parking lights
  • Spark plugs

  • 103. 
    . Which of the following factors adversely affects the capacity of the leadacid battery ?

  • Temperature of surroundings
  • Specific gravity of electrolyte
  • Rate of discharge
  • All of the above

  • 104. 
    . Cells are connected in parallel to

  • increase the efficiency
  • increase the current capacity
  • increase the voltage output
  • increase the internal resistance

  • 105. 
    . A constant-voltage generator has

  • minimum efficiency
  • minimum current capacity
  • low internal resistance
  • high internal resistance

  • 106. 
    . Satellite power requirement is provided through

  • solar cells
  • dry cells
  • nickel-cadmium cells
  • lead-acid batteries
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