In a series circuit, does the current remain the same through all components?

• A. It varies with resistance
• B. It depends on voltage
• C. No
• D. Yes

Answer: (D)

In a series circuit, the current is the same through every component because there's only one path for electrons. Since charges flow in a single loop, the amount of current entering a component must equal the amount leaving it, so the current is constant throughout the loop.

The total current is set by the source voltage and the total resistance: I = V / R_total. The equal current through each component means the voltage across each part can differ, depending on its resistance. Specifically, the voltage drop across a component is V_i = I × R_i, so larger resistances take a larger share of the total voltage, while the current stays the same.

For example, with a 12 V source and resistors of 4 Ω and 6 Ω in series, the total resistance is 10 Ω, giving a current of 1.2 A that flows through both resistors. The voltage drops would be V = I × R, so the 4 Ω resistor drops 4.8 V and the 6 Ω resistor drops 7.2 V, even though the current is identical in both.

Thus, the correct idea is that current remains the same through all components in a series circuit.