A current I flows through a potential difference V in an electrical circuit containing a resistance R. The product of V and I, i.e., VI may be understood as

In an electrical circuit, the product of potential difference (V) and current (I) represents the electrical power (P = VI). According to the law of conservation of energy, if a circuit is purely resistive, the source energy is continually dissipated entirely in the form of heat [2]. This power represents the rate at which electrical energy is converted into thermal energy. While 'heat generated' refers to total energy (W = VIt), the product VI specifically denotes the rate of energy transfer, which is power [1]. In the context of a resistor operating in a steady state, this electrical power is equivalent to the thermal power radiated or dissipated by the circuit to its surroundings [2]. Therefore, VI is best understood as the thermal power radiated/dissipated by the circuit [2].

Sources

1. [2] Science , class X (NCERT 2025 ed.) > Chapter 11: Electricity > 11.7 HEA 11.7 HEA11.7 HEATING EFFECT OF ELECTRIC CURRENT > p. 188
2. [1] Science , class X (NCERT 2025 ed.) > Chapter 11: Electricity > What you have learnt > p. 192