The equation r(t) = r0[1 + α(t - t0)] describes how the resistance of a material changes with temperature over time. In this equation, 'r(t)' represents the resistance at a given temperature 't', 'r0' is the initial resistance at a reference temperature 't0', and 'α' is the temperature coefficient of resistance. This relationship is crucial for understanding how temperature affects the performance of electrical devices, which is essential in electrical engineering.