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

The formula to calculate total resistance in a series circuit is given by the summation of all individual resistances. This means that the total resistance, denoted as RT, is simply the sum of each resistor in the circuit. When resistors are connected in series, the current flowing through each resistor is the same, and the total resistance can be calculated by adding together the resistance values of each resistor.

In a series circuit, the resistors do not split the current; therefore, the total resistance contributes to the overall opposition to the flow of electricity. This is why the formula is RT = R1 + R2 + R3 + ... + Rn. Each individual resistance (R1, R2, R3, and so on) directly adds to the total resistance encountered by the current.

Other options do not accurately represent total resistance in a series circuit. For instance, multiplying resistances (as in the first option) is characteristic of parallel circuits, while the other options involve incorrect mathematical operations that do not correspond to the principles of series resistance.