batteries and current sources

Question 1

electric cells

Answer 1

chemical energy is converted into electrical energy.in the case of primary cells , the actin is not reversable

Question 2

secondary cells can be recharged

Answer 2

passing current through the the opposite direction to the current floe w during discharge.

Question 3

essential materials of any cells

Answer 3

two electrodes of dieffernt type of material and electrolyte.

Question 4

primary cells the elcttrolyte

Answer 4

is combined with with an absorbant material form of a paste

Question 5

in an open circuit a leclanche cell

Answer 5

1,5 volts

Question 6

most generally used primmary cel is the

Answer 6

leclanche cell

Question 7

uses of miniature cells

Answer 7

wrist watches , hearing aidds guideed missiles. cells such aas mucury oxide , silver oxide were deveeloped

Question 8

nickel caadnium cells

Answer 8

alkaline electrolyte, are rechargeble , minature , computers, video camaras for slightly larger uses, slab shaped. much larger ones are used for aircrafts

Question 9

lead acid cells

Answer 9

mostly used in motors and is a secondary cell

Question 10

emf of lead acid cell

Answer 10

depdends on the materials used to manufacture the cell

Question 11

reletive density

Answer 11

ratio of the mass of a unit voolume of the electrolyte to the mass of the same vollume of water is know as the relative density. it is specified by the manufacturer.it ussually between 1,230 to 1,280

Question 12

what happens to relative density during discharge?

Answer 12

decreases

Question 13

capacity of a lead acid cell

Answer 13

20 hour ampere hour rating. refers to the constant current through which the batterycan deliver for 20 hours before the terminal pd drops below 1,85 volts per cell

Question 14

the capacity of a lead acid cell depends on

Answer 14

number and the size of plates
rate of discharge
temp
age and the condition of the cell.

Question 15

fully charged lead acid cells state

Answer 15

positive plates haave a choclate brown colour and negative light grey
relative deensity of electrolyte increases.

Question 16

discharged lead acid cell state

Answer 16

terminal voltage drops below 1,85
specific gravity of the cell drops.
postive and negative terminals have matt grey colour

Question 17

5 ways to care for lead acid cell

Answer 17

cells should not be discharged below 80% of their capacity
vent holes in the filter plugs must be kept open
they should not be left in discharged state and musst be recherged as soon as possible.
acid may not be addes to the battery…

Question 18

diffferern types of lead acid cells available today

Answer 18

conventional, kow mainatainance , maintainance free , hybrifd long life types

Question 19

leisure batteries

Answer 19

boats caravans can withstand fequent deeep discharge an dcharge cycles

Question 20

6 factors that should be considered when purchasing a cell

Answer 20

voltage required by the load
internal resistance of the cell
operting tempertures
physical size of the cell and mass
life expectancy of the cell
cost of the cell
rechargeble or not
storage life of a cell

Question 21

5 methods of producing elecrtricity

Answer 21

chemical reaction
electromagnetic induction
solar energy conversions
heat
friction