What happens to the total resistance in a series circuit when more resistors are added in series?

• A. It decreases.
• B. It increases.
• C. It stays the same.
• D. It becomes zero.

Answer: (B)

In a series circuit, resistors share the same current and the total opposition to that current is the sum of every resistor’s value. Adding another resistor in series adds an additional amount of resistance to the path, so the overall resistance rises. With a fixed supply voltage, that higher total resistance means the current must decrease (I = V / R_total). For example, two 5-ohm resistors in series equal 10 ohms, and a third 5-ohm resistor makes 15 ohms, reducing current each time you add more in series. The total cannot decrease or stay the same when you add resistors in series; it also won’t be zero unless the circuit is open or the resistance is effectively infinite.