What is the formula to calculate the total resistance in a series circuit?

In a series circuit, the total resistance is calculated by simply adding together the individual resistances of each component connected in the series. This is because the same current flows through all the resistors in series, and the total opposition to that current is the sum of all the resistances. Therefore, the correct formula to determine the total resistance in such a configuration is R_total = R1 + R2 + R3 + ... + Rn. This illustrates the fundamental principle of series circuits, where resistors contribute directly to the overall resistance.

The other formulas provided relate to different contexts. One formula involves the reciprocal of resistances, which is used for parallel circuits, not series. Other formulas concerning voltage (V) and current (I) pertain to Ohm’s law and power calculations, rather than directly calculating resistance in a series circuit. Understanding these concepts allows for a clearer differentiation between how resistors operate in series versus in parallel and helps reinforce the foundational principles of electrical circuits.