What total voltage is required to supply two elements wired in series, with each rated at 120 volts?

When electrical elements are wired in series, the total voltage required is the sum of the individual voltage ratings of each element. In this case, each element is rated at 120 volts. Therefore, to find the total voltage, you add the voltage ratings together:

120 volts + 120 volts = 240 volts.

This is why the correct choice is 240 volts. In a series circuit, the same current flows through both elements, and the voltage supplied must be sufficient to account for the voltage drop across each element. Thus, when connecting two 120-volt elements in series, a total of 240 volts is necessary to ensure both elements receive their rated voltage for proper operation.