RRB Technician Grade I 13 March 2026 Paper

Concept:Ohm's law states that the current through a conductor is directly proportional to the potential difference across it, provided physical conditions such as temperature remain constant.Explanation:Ohm's law is mathematically written as $V = IR$, where $V$ is the voltage, $I$ is the current, and $R$ is the resistance.This law is valid only when the physical conditions of the conductor, especially temperature, remain unchanged.When the temperature of the conductor increases, the resistivity of the material changes, which alters the resistance.In metallic conductors, resistance increases with temperature, making the $V$–$I$ relationship nonlinear.Similarly, non-ohmic materials such as semiconductors and diodes do not obey Ohm's law.Therefore, Ohm's law may not hold true when the temperature of the conductor increases.Option A (constant temperature), Option B (linear $V$–$I$ relation), and Option D (metallic conductor) all describe conditions where Ohm's law is valid.Answer:The temperature of the conductor increases (Option C).