Multiple Choice Questions(MCQ) on Electrolysis and Batteries for Electrical Engineering
1. The charge required to liberate one gram equivalent of any substance is known as ______ constant
(a) time
(b) Faraday’s
(c) Boltzman
(d) Faraday’s and Boltzman
Ans: b
2. During the charging of a lead-acid cell
(a) its voltage increases
(b) it gives out energy
(c) its cathode becomes dark chocolate brown in colour
(d) specific gravity of H2SO4 decreases
Ans: a
3. 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.
Ans: b
4. The output voltage of a charger is
(a) less than the battery voltage
(b) higher than the battery voltage
(c) the same as the battery voltage
(d) none of the above
Ans: b
5. During the charging and discharging of a nickel-iron cell
(a) corrosive fumes are produced
(b) water is neither formed nor absorbed
(c) nickel hydroxide remains unsplit
(d) its e.m.f. remains constant
Ans: b
6. 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
Ans: c
7. A dead storage battery can be revived by
(a) adding distilled water
(b) adding so-called battery restorer
(c) a dose of H2SO4
(d) none of the above
Ans: d
8. Trickle charging of a storage battery helps to
(a) maintain proper electrolyte level
(b) increase its reserve capacity
(c) prevent sulphation
(d) keep it fresh and fully charged
Ans: d
9. In a lead-acid cell dilute sulphuric acid (electrolyte) approximately comprises the following
(a) one part H2O, three parts H2SO4
(b) two parts H2O, two parts H2SO4
(c) three parts H2O, one part H2SO4
(d) all H2S04
Ans: c
10. When the lead-acid cell is fully charged, the electrolyte assumes _____ appearance
(a) dull
(b) reddish
(c) bright
(d) milky
Ans: d
11. The internal resistance of an alkali cell is nearly _____ times that of the lead-acid cell.
(a) two
(b) three
(c) four
(d) five
Ans: d
12. The average charging voltage for alkali cell is about
(a) 1 V
(b) 1.2 V
(c) 1.7 V
(d) 2.1 V
Ans: c
13. The active material of the positive plates of silver-zinc batteries is
(a) silver oxide
(b) lead oxide
(c) lead
(d) zinc powder
Ans: a
14. Lead-acid cell has a life of nearly charges and discharges
(a) 500
(b) 700
(c) 1000
(d) 1250
Ans: d
15. Life of the Edison cell is at least
(a) five years
(b) seven years
(c) eight years
(d) ten years
Ans: a
16. Negative plate of an Edison cell is made of
(a) copper
(b) lead
(c) iron
(d) silver oxide
Ans: c
17. In ______ system the charging current is intermittently controlled at either a maximum or minimum value
(a) two rate charge control
(b) trickle charge
(c) floating charge
(d) an equalizing charge
Ans: a
18. Undercharging....
(a) reduces specific gravity of the electrolyte
(b) increases specific gravity of the electrolyte
(c) produces excessive gassing
(d) increases the temperature
Ans: a
19. 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
Ans: d
20. 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
(a) 6 parts of acid to 4 parts of water
(b) 4 parts of acid to 4 parts of water
(c) 4 parts of acid to 6 parts of water
(d) 4 parts of acid to 8 parts of water
Ans: c
21. If a battery is wrongly connected on charge following will happen
(a) current delivered by the battery will be high
(b) current drawing will be nil
(c) current drawing will be very small
(d) current drawing will be very high
Ans: d
22. Life of the batteries is in the following ascending order.
(a) Lead-acid cell, Edison cell, Nickel cadmium cell
(b) Lead-acid cell, Nickel-cadmium cell, Edison cell
(c) Edison cell, Nickel-cadmium cell, lead-acid cell
(d) Nickel-cadmium cell, Edison cell, lead-acid cell
Ans: a
23. Level of electrolyte in a cell should be _____ the level of plates
(a) below
(b) equal to
(c) above
(d) none of the above
Ans: c
24. During discharge, the active material of both the positive and negative plates is changed to
(a) Pb
(b) Pb02
(c) PbO
(d) PbS04
Ans: d
25. _____ of electrolyte indicates the state of charge of the battery
(a) colour
(b) mass
(c) viscosity
(d) specific gravity
Ans: d
26. Dry cell is modification of
(a) Deniell cell
(b) Leclanche cell
(c) Lead-acid cell
(d) Edison cell
Ans: b
27. In alkaline cell the electrolyte is
(a) dilute sulphuric acid
(b) concentrated sulphuric acid
(c) NaOH
(d) KOH
Ans: d
28. All the electrical connections between the battery and vehicle should be by
(a) thin aluminium wires
(b) thin copper wires
(c) rigid cables
(d) flexible cables
Ans: d
29. Weston standard cell at 20°C has voltage of ____ volts.
(a) 0.8
(b) 0.9
(c) 1.0187
(d) 1.5
Ans: c
30. Which of the following primary cells has the highest voltage ?
(a) Manganese-alkaline
(b) Carbon-zinc
(c) Lithium
(d) Mercury
Ans: c
31. Which of the following primary cells has the lowest voltage ?
(a) Lithium
(b) Zinc-chloride
(c) Mercury
(d) Carbon-zinc
Ans: c
32. 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
Ans: b
33. Which of the following battery is used for air-craft ?
(a) Lead-acid battery
(b) Nickel-iron battery
(c) Dry cell battery
(d) Silver oxide battery
Ans: b
34. Under normal charging rate, the charging current should be
(a) 10% of capacity
(b) 20% of capacity
(c) 30% of capacity
(d) 40% of capacity
Ans: a
35. When two batteries are connected in parallel, it should be ensured that
(a) they have same e.m.f.
(b) they have same make
(c) they have same ampere-hour capacity
(d) they have identical internal resistance
Ans: a
36. The common impurity in the electrolyte of lead-acid battery is
(a) chlorine
(b) dust particles
(c) lead crystals
(d) iron
Ans: d
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#Electrolysis and Batteries mcq.
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