Which formula would you use to calculate the total resistance in a series circuit?

The total resistance in a series circuit is calculated by adding up all the individual resistances. This is because in a series configuration, the current flows through each resistor one after another, so the overall resistance is a simple sum of all resistances in the path. Each resistor contributes to the total opposition to current flow, hence the formula:

Total Resistance (Rtotal) = R1 + R2 + R3 + ... + Rn.

This method allows you to find the effective resistance that dictates how much current will flow through the entire circuit when a voltage is applied. The other options represent different operations that do not apply to the principles of series circuits.