lactometer

hydrometer

hygrometer

voltmeter

10 mm below the top of the plates

25 mm below the top of the plates

exactly at the top of the plates

10 to 15 mm above the top of the plates

1.2 V

1.5 V

1.8 V

2.0 V

40%

50%

60%

70%

cylindrical cell and rectangular cell

dry cell and wet cell

primary cell and secondary cell

acid cell and alkali cell