| 
56 | 
What is meaning of the Ah rating of cell? | 
  | 
 | 
 
The Ah rating of cell indicates its discharge rate. 
 
 | 
  | 
57 | 
Describe the factors to be affecting the capacity of the cell. | 
  | 
 | 
 
The capacity of cell is affected
  by 
 
TemperatureDischarge rateDensity of electrodeQuantity of active material 
 
 | 
  | 
58 | 
Describe the effect of density of electrolyte on the cell capacity. | 
  | 
 | 
 
As the density of electrolyte increases, the cell capacity also
  increases. 
 | 
  | 
59 | 
Describe the effect of temperature on the capacity of the secondary cell. | 
  | 
 | 
 
High temperature 
 
Chemical reaction takes place very fast.The resistance of the acid decreases.The capacity of the cell increases as the temperature increases however it is not advisable to work cell above 400 C. 
 
Low temperature 
 
Chemical reaction takes place very slowly.Chemical reaction between acid and terminal pots, lead alloy grid.The resistance of the acid increases.The capacity of the cell decreases with decrease in the temperature. 
 
 | 
  | 
60 | 
State the specific gravity of the electrolyte during charging and
  discharging of lead acid cell. | 
  | 
 | 
 
The specific gravity of the charged lead acid cell is 1.21 whereas it
  is 1.18 during discharging. 
 | 
  | 
61 | 
What is meaning of the sulphation? | 
  | 
 | 
 
Sulphation  
 
If the cell is not fully charged periodically, the lead sulphate
  formed during discharging which is not converted back into PbO2
  and Pb. There will result in reduction of PbSO4 which is deposited
  on the plates. This is called as sulphation.The sulphation is possible if the cell is overcharged or left
  uncharged for long time. 
 
 | 
  | 
62 | 
Describe the effect of sulphation on the cell performance. | 
  | 
 | 
 
The internal resistance of the cell increases due to sulphation. This
  will reduce its efficiency and capacity. 
 | 
  | 
63 | 
 How to resolve the sulphation
  problem in the cell? | 
  | 
 | 
 
The problem of the sulphation is resolved by successive overcharge.
  The cell gets two consecutive charges without discharge.  
 | 
  | 
64 | 
Describe the different types of alkaline battery. | 
  | 
 | 
 
Types of alkaline battery 
 
Nickel – Iron ( Edison )Nickel – Cadmium ( NIFE ) 
 
 | 
  | 
65 | 
Describe the advantages and disadvantages of Edison battery. | 
  | 
 | 
 
Advantages 
 
Lighter in weightCompact constructionHigh mechanical strengthRequires less quantity of electrolyte as compared to lead – acid
  batteryWithstand against rapid charging and dischargingElectrolyte corrosion liquid does not occur.Electrolyte does not deteriorate even if battery is left discharged
  for long time. 
 
Disadvantages 
 
Initial high costLow watt hour efficiency and ampere hour efficiency as compared to
  lead acid battery. 
 
 | 
 
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