In a series circuit, does the same current flow through all resistors?

• A. False
• B. Only when voltage remains constant
• C. Only when the resistors are equal
• D. True

Answer: (D)

In a series circuit, there’s only one path for the current, so the same amount of charge flows through every component in that path. That means the current is identical through each resistor, no matter their individual values. This is why the total current I is determined by the overall supply and the sum of the resistances: I = V_total / (R1 + R2 + ...). While the current stays the same through all resistors, the voltage drops across them depend on their values (larger resistance drops more voltage, since V = I·R). If the path is opened, current stops everywhere; if a component changes value, the current changes but remains the same through all components in the path. So the statement that the current is the same through all resistors is the correct description of a series circuit.