Ohm's law implication in a series circuit: If the series current in a circuit doubles, which statement best describes the corresponding change (assume the total resistance remains constant)?

Introduction:
Ohm's law connects voltage, current, and resistance. When one quantity changes, the others respond according to V = I * R. Interpreting these relationships correctly depends on stating which parameter is held constant, a common source of confusion in quick conceptual questions.

Given Data / Assumptions:

• The circuit is series and resistive.
• Total resistance R_total remains constant (no component value change).
• The observed change is that current I doubles.

Concept / Approach:

With R fixed, voltage and current are directly proportional. If current increases by a factor, voltage across the same resistance must increase by the same factor to satisfy Ohm's law. Therefore, doubling current requires doubling voltage when resistance is unchanged.

Step-by-Step Solution:

Verification / Alternative check:

Numeric example: R = 100 Ω. If I1 = 0.5 A → V1 = 50 V. Doubling current to I2 = 1.0 A requires V2 = 100 V, exactly double, confirming the rule when R is fixed.

Why Other Options Are Wrong:

• resistance is halved / resistance is doubled: Resistance is a physical property unless changed; assumption states R is constant.
• voltage is reduced: Contradicts direct proportionality when R is constant.
• power is halved: Power P = V * I; if both V and I double (R fixed), power quadruples, not halves.

Common Pitfalls:

• Answering 'resistance is halved' by implicitly assuming a constant-voltage source without reading the assumption about constant R; the question here specifies R constant and asks what must change.
• Ignoring that multiple scenarios can produce the same current change; always check which parameter is constrained.

Final Answer:

voltage is doubled