What is the formula for calculating the total resistance of only 2 resistors in parallel?

The formula for calculating the total resistance of two resistors in parallel is accurately represented in the choice that indicates R(t) = R(1) x R(2) / (R(1) + R(2)). This formula arises from the fundamental principles of electrical circuits where the inverse of total resistance in a parallel circuit is equal to the sum of the inverses of the individual resistances.

When two resistors are connected in parallel, they provide multiple paths for current to flow. The total current flowing through the circuit is the sum of the currents through each resistor. Since the voltage across each resistor in parallel is the same, Ohm's Law (V = IR) can be applied to find the total current and ultimately the total resistance. The derived formula helps in effectively calculating how two resistors interact when they are placed in parallel, showing that the total resistance is less than the smallest individual resistance.

This is crucial for understanding how parallel circuits operate, particularly in fire alarm systems where resistors may be utilized to create various conditions for detection and alerting mechanisms.