Which one of the following statements regarding Ohm's law is not correct?

Ohm's law is an empirical rule stating that the current through a conductor is directly proportional to the potential difference across it, provided physical conditions like temperature remain constant [1]. A device or material is considered 'Ohmic' when its resistance remains constant, independent of the magnitude and polarity of the applied potential difference or the direction of the electric field. However, statement 4 is incorrect because Ohm's law is not a fundamental law of nature like Maxwell's equations; it is a generalization that is not always obeyed. Most materials, even homogeneous ones, will break down or exhibit non-ohmic behavior under a sufficiently strong electric field. Therefore, it is false to claim that all homogeneous materials obey the law irrespective of whether the field is within range or strong, as strong fields typically lead to deviations from linearity.

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 11: Electricity > What you have learnt > p. 192