Short notes
Objective questions (Answers are given below)
- Active materials of a lead-acid cell are :
(a) lead peroxide (b) sponge lead
(c) dilute sulphuric acid (d) all the above - During the charging of a lead-acid cell :
(a) its cathode becomes dark chocolate brown
in colour
(b) its voltage increases
(c) it gives out energy
(d) specific gravity of H2SO4 is decreased - The ratio of Ah efficiency to Wh efficiency of a
lead-acid cell is :
(a) always less than one (b) just one
(c) always greater than one
(d) either (a) or (b) - The capacity of a cell is measured in :
(a) watt-hours (b) watts
(c) amperes (d) ampere-hours - The capacity of a lead-acid cell does NOT
depend on its :
(a) rate of charge
(b) rate of discharge
(c) temperature
(d) quantity of active material - As compared to constant-current system, the
constant-voltage system of charging a lead-acid
cell has the advantage of :
(a) avoiding excessive gassing
(b) reducing time of charging
(c) increasing cell capacity
(d) both (b) and (c). - Sulphation in a lead-acid battery occurs due to:
(a) trickle charging
(b) incomplete charging
(c) heavy discharging (d) fast charging - The active materials of a nickel-iron battery are.
(a) nickel hydroxide
(b) powdered iron and its oxides
(c) 21% solution of caustic potash
(d) all of the above. - During the charging and discharging of a nickel
iron cell :
(a) its e.m.f. remains constant
(b) water is neither formed nor absorbed
(c) corrosive fumes are produced
(d) nickel hydroxide remains unsplit - As compared to a lead-acid cell, the efficiency
of a nickel-iron cell is less due to its :
(a) lower e.m.f.
(b) smaller quantity of electrolyte used
(c) higher internal resistance
(d) compactness. - Trickle charging of a storage battery helps to :
(a) prevent sulphation
(b) keep it fresh and fully charged
(c) maintain proper electrolyte level
(d) increase its reserve capacity - A dead storage battery can be revived by :
(a) a dose of H2SO4
(b) adding so-called battery restorer
(c) adding distilled water
(d) none of the above - The sediment which accumulates at the bottom
of a lead-acid battery consists largely of :
(a) lead-peroxide (b) lead-sulphate
(c) antimony-lead alloy (d) graphite - The reduction of battery capacity at high rates
of discharge is primarily due to :
(a) increase in its internal resistance
(b) decrease in its terminal voltage
(c) rapid formation of PbSO4 on the plates
(d) non-diffusion of acid to the inside active
materials. - Floating battery systems are widely used for :
(a) power stations
(b) emergency lighting
(c) telephone exchange installation
(d) all of the above - Any charge given to the battery when taken off
the vehicle is called :
(a) bench charge (b) step charge
(c) float charge (d) trickle charge
- d 2. b 3. c 4. d 5. a 6. d 7. b 8. d 9. b 10. c 11. b 12. d 13. c 14. c 15. d 16. a