In a series circuit, which statement is true about current and voltage?

• A. In a series circuit, the current varies through all elements; voltages across components add up to the source.
• B. The current is the same through all elements; voltages across components add up to the source.
• C. In a series circuit, the voltage across each element is the same, and the current through each element is different.
• D. The total current is determined by the first element.

Answer: (B)

In a series circuit, current is the same through every element and the voltages across the components add up to the source. Since there’s only one path for current, it cannot split, so the same current flows through each element. The source voltage is dropped across the components, and the sum of those individual voltage drops equals the source voltage. According to Ohm’s law, the current is I = V_total / R_total, so the current is set by the total resistance of all series elements. The voltage across each element is V_i = I × R_i, so voltages add up to the source while each component might take a different share depending on its resistance. For two resistors in series, the current is the same in both, while the resistor with larger resistance takes a larger portion of the total voltage.

The other statements don’t fit because in a series circuit the current does not vary between elements, the voltages are not all the same, and the total current is not determined by the first element but by the entire circuit’s total resistance and the source voltage.