Which formula correctly calculates total resistance in a parallel circuit?

The correct calculation for total resistance in a parallel circuit is given by the formula for the reciprocal of the sum of the reciprocals of the individual resistances, expressed as RT = 1/(1/R1 + 1/R2 + 1/R3). This formula reflects the unique nature of parallel circuits, where current can flow through multiple pathways simultaneously.

In a parallel configuration, the voltage across each resistor is the same, leading to the currents through each resistor being additive rather than the resistances themselves. This results in a lower total resistance compared to the individual resistances. By taking the reciprocal of the sum of the reciprocals, you effectively find the total resistance that allows the maximum total current to pass through the circuit.

Other formulas mentioned serve different purposes. One calculates total resistance in a series circuit, another relates voltage and current (Ohm's Law), and the fourth defines the relationship between voltage, current, and resistance, but they do not apply to determining the total resistance in a parallel arrangement. Therefore, choosing the correct formula is critical for accurate calculations in parallel circuits.