If the resistance in a series circuit doubles, what happens to the current?

If the resistance in a series circuit doubles, what happens to the current?

• A. The current doubles
• B. The current remains the same
• C. The current is halved
• D. The current becomes zero

Answer: (C)

Current in a circuit with a fixed voltage is inversely related to resistance. In a series circuit, the same current flows through all components, and the total resistance is the sum of the resistances. If the total resistance doubles while the voltage stays the same, the current becomes half as large: I_new = V / (2R) = (1/2) × (V/R) = I_old/2. So the current is halved. It wouldn’t double or stay the same, and it wouldn’t drop to zero unless the voltage or resistance changed to an extreme (infinite resistance or zero voltage).

Current in a circuit with a fixed voltage is inversely related to resistance. In a series circuit, the same current flows through all components, and the total resistance is the sum of the resistances. If the total resistance doubles while the voltage stays the same, the current becomes half as large: I_new = V / (2R) = (1/2) × (V/R) = I_old/2. So the current is halved. It wouldn’t double or stay the same, and it wouldn’t drop to zero unless the voltage or resistance changed to an extreme (infinite resistance or zero voltage).