A battery of 6 cells will show a drop of _____ volts from fully charged state to fully discharged state.

1
1.5
2.4
2.9

The correct answer is B. 1.5 volts.

A battery of 6 cells will show a drop of 1.5 volts from fully charged state to fully discharged state. This is because each cell in a battery has a voltage of 1.5 volts, and when the battery is fully discharged, all of the cells are discharged.

Option A is incorrect because it is the voltage of a single cell in a battery. Option C is incorrect because it is the voltage of two cells in a battery. Option D is incorrect because it is the voltage of three cells in a battery.