To decrease the current through a specific resistor in a parallel network, you should:

• A. Decrease that resistor's resistance
• B. Increase that resistor's resistance
• C. Increase supply voltage
• D. Add a second branch

Answer: (B)

In a parallel network the voltage across each branch is the same, so the current through a given resistor is set by I = V/R. With the supply voltage fixed, increasing the resistance of that specific branch reduces the current flowing through it because the current is inversely related to resistance. Decreasing the resistance would increase the current, raising the supply voltage would push more current through that branch, and adding a second branch doesn’t change the voltage across the existing branch in an ideal source, so it doesn’t reduce that resistor’s current. Hence, the way to decrease the current through that resistor is to increase its resistance.