In the diagram above, what would happen to the current I, if another resistor, R2, is connected in parallel to R1?

Answer Details

When another resistor, R2, is connected in parallel to R1, the total resistance of the circuit decreases. As a result, the current I in the circuit will increase because the current flowing through each resistor is inversely proportional to the resistance. Therefore, option C is correct: "It will increase because the effective resistance will decrease."