How do you calculate total resistance in a parallel circuit?

In a parallel circuit, the total resistance is calculated using the reciprocal formula, which states that the reciprocal of the total resistance (1/R_total) is equal to the sum of the reciprocals of each individual resistance in the circuit. This is because, in a parallel configuration, each resistor provides a separate path for current to flow, enabling the overall current to increase while the voltage across each resistor remains the same.

When you add resistances in parallel, the effective total resistance decreases. This can be easily seen in the formula: for example, if two resistors have resistances of R_1 and R_2, instead of simply adding them together, you take the reciprocal of each and sum that. The more parallel paths there are, the lower the total resistance becomes, reflecting the greater ability to conduct electricity through the circuit.

Thus, option C accurately captures the mathematical relationship needed to find the total resistance in a parallel circuit, highlighting the unique characteristics of current flow in that setup.