Ohm's law defines

Ohm's law states that the potential difference (V) across a metallic wire is directly proportional to the current (I) flowing through it, provided temperature remains constant [1]. This relationship is expressed as V = IR, where 'R' is a constant known as resistance [1]. While the law describes the relationship between voltage and current, its primary significance is defining the physical property of resistance for a conductor [1]. Resistance is the property of a conductor to resist the flow of charges [1]. It is defined by the ratio of potential difference to current (R = V/I). Therefore, Ohm's law provides the fundamental definition of electrical resistance as a constant of proportionality for ohmic materials [1].

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 11: Electricity > Figure 11.3 > p. 176