What happens to the current in a series circuit when you add another resistor?

What happens to the current in a series circuit when you add another resistor?

• A. Current increases
• B. Current remains the same
• C. Current becomes zero
• D. Current decreases

Answer: (D)

In a series circuit, the current is set by the total resistance the voltage source has to push current through. Ohm’s law I = V / R_total means that when you add another resistor in series, R_total increases. With the same voltage, a larger R_total gives a smaller current. The current that flows through every component in a series loop is the same, so the whole circuit experiences this reduced current. So adding a resistor in series causes the current to decrease. For example, adding another resistor in series increases resistance, and with the same supply, the current drops accordingly. The current does not rise or stay the same, and it won’t become zero unless the circuit is opened or infinite resistance is created.

In a series circuit, the current is set by the total resistance the voltage source has to push current through. Ohm’s law I = V / R_total means that when you add another resistor in series, R_total increases. With the same voltage, a larger R_total gives a smaller current. The current that flows through every component in a series loop is the same, so the whole circuit experiences this reduced current. So adding a resistor in series causes the current to decrease. For example, adding another resistor in series increases resistance, and with the same supply, the current drops accordingly. The current does not rise or stay the same, and it won’t become zero unless the circuit is opened or infinite resistance is created.