Ohm's Law: Current and Voltage Relationship

The question describes a fundamental principle in electricity. The statement specifies that the electric current flowing through a metallic wire is directly proportional to the potential difference (voltage) across its ends, as long as the temperature remains the same. This relationship is defined by Ohm's law.

Understanding Ohm's Law

• Ohm's law states that the current (\(I\)) flowing through a conductor is directly proportional to the voltage (\(V\)) across its ends and inversely proportional to the resistance (\(R\)) of the conductor, provided the temperature and other physical conditions remain unchanged.
• Mathematically, this is represented as: \( V \propto I \) or \( V = IR \) where \(R\) is the constant of proportionality, representing resistance.
• The condition 'provided its temperature remains the same' is crucial for Ohm's law to hold true for metallic conductors.

Why Other Laws Don't Apply

• Ampere's law relates magnetic fields to electric currents.
• Coulomb's law describes the electrostatic force between charges.
• Joule's law deals with the heat generated by electric current (\(H = I^2Rt\)).

Therefore, the law defining the direct proportionality between current and potential difference at constant temperature is Ohm's law.