What is the formula used to determine the total current in a series circuit?

In a series circuit, the total current flowing through the circuit remains constant and is the same at every point in the circuit. This is due to the characteristics of series connections, where the same charge that moves through one component must also flow through every other component connected in the series.

The formula that accurately represents this relationship is that the total current (It) is equal to the current flowing through each individual component (I₁, I₂, I₃, etc.), as they all have the same value in a series circuit. Therefore, the correct equation signifies that It is equal to the individual currents in the circuit, reflecting the fundamental property of current continuity in series circuits.

The other options present different concepts that do not apply to how current functions in a series circuit. For instance, summing or subtracting currents as shown in some other options does not represent the unchanging nature of current within a series configuration. Additionally, multiplying currents would only apply in different scenarios, such as when dealing with parallel circuits or other more complex situations, which is not relevant to the question at hand.