In a parallel circuit, how does adding another resistor in parallel affect the total resistance?

In a parallel circuit, how does adding another resistor in parallel affect the total resistance?

• A. Increases
• B. Decreases
• C. Stays the same
• D. Doubles

Answer: (B)

In a parallel circuit, adding another resistor provides an extra path for current. This increases the total conductance (the ability of the network to carry current), which means the overall or equivalent resistance drops. The formal relationship is 1/Req = 1/R1 + 1/R2 + …, so each new parallel path adds to the sum of conductances and pushes Req lower. For equal resistors, three in parallel give one-third of a single resistor’s value, two give half, and so on. So, the total resistance decreases when you add another resistor in parallel.

In a parallel circuit, adding another resistor provides an extra path for current. This increases the total conductance (the ability of the network to carry current), which means the overall or equivalent resistance drops. The formal relationship is 1/Req = 1/R1 + 1/R2 + …, so each new parallel path adds to the sum of conductances and pushes Req lower. For equal resistors, three in parallel give one-third of a single resistor’s value, two give half, and so on. So, the total resistance decreases when you add another resistor in parallel.