21) The charge condition of a secondary cell can be checked by :

its terminal voltage

the colour of its electrolyte

the level of its electrolyte

its terminal voltage and specific gravity of its electrolyte

Answer is:

its terminal voltage and specific gravity of its electrolyte

1.18

1.15

1.25

1.35

Answer is:

alkaline batteries only

alkaline and solar batteries

alkaline and dry batteries

nickel-cadmium and nickel-iron batteries

Answer is:

water to hydrochloric acid

sulphuric acid to water

hydrochloric acid to water

water to sulphuric acid

Answer is:

the thickness of plates

the distance between the plates

the number and area of plates

the strength of electrolyte

Answer is: