What is the mathematical expression for calculating series resistance?

The correct way to calculate series resistance involves adding together the resistances of individual resistors connected in series. The total resistance (Rt) in a series circuit is the sum of the resistances of all components. This is expressed mathematically as Rt = R₁ + R₂ + R₃ + R₄..., where each R represents the resistance value of each resistor in the series.

When resistors are connected in series, the electrical current flowing through them is the same, but the voltage across each resistor can differ depending on its resistance value. Therefore, to find the total resistance that the current encounters, you simply add their resistance values together.

Other options presented represent incorrect methods for calculating resistance. For instance, multiplying resistances (as indicated in one option) does not apply to series circuits, as that calculation would misrepresent how resistors function together in that configuration. The subtraction of resistances is also invalid as it does not reflect how series connections operate. Thus, the addition of the resistance values provides a clear and accurate representation of the total resistance in a series circuit configuration.