What is the nominal voltage of a fully charged lead-acid battery consisting of six cells?

A fully charged lead-acid battery typically consists of six cells connected in series. Each cell has a nominal voltage of approximately two volts when fully charged. Therefore, when you multiply the number of cells (six) by the nominal voltage per cell (two volts), you arrive at a total nominal voltage of twelve volts. This makes twelve volts the standard for a fully charged lead-acid battery comprising six cells.

The other options do not align with the standard configuration and voltage calculation of these batteries. Six volts would apply to a battery with three cells, one hundred twenty volts would suggest a much larger number of cells combined, and twenty-four volts is characteristic of a configuration with twelve cells. Therefore, twelve volts stands out as the correct answer for a typical six-cell configuration of a lead-acid battery.