When a third resistor is added in parallel to an existing circuit with two resistors, what effect does this have on the current drawn from the battery?

When a third resistor is added in parallel to a circuit that already has two resistors, the overall resistance of the circuit decreases. This is because parallel resistors provide additional paths for current to flow, effectively lowering the total resistance according to the formula for resistors in parallel. The total resistance (R_total) for parallel resistors can be calculated using the equation:

1/R_total = 1/R1 + 1/R2 + 1/R3

As more resistors are added in parallel, the total resistance approaches zero but never actually reaches it. This reduction in total resistance leads to an increase in the overall current drawn from the battery, as stated by Ohm’s Law (I = V/R), where an increase in voltage (which remains constant in this case) and a decrease in resistance results in an increased current.

Therefore, adding that third resistor in parallel indeed increases the current flowing from the battery.