What is the formula to determine the maximum current in an RC circuit?

The formula that accurately represents the maximum current in an RC (resistor-capacitor) circuit is derived from the relationship established when the capacitor is fully charged. The maximum current occurs when the switch in the circuit is initially closed, and the capacitor is not yet charged, which implies that the entire voltage of the source is applied across the resistor.

In an RC circuit, the maximum current can indeed be expressed as I = E/R, where E is the electromotive force (or voltage) of the power supply and R is the resistance. This is because, at the moment of closing the switch, the voltage across the capacitor is zero and the entire voltage is dropped across the resistor, which allows us to calculate the initial or maximum current using Ohm's Law.

This context helps to understand why C is not the correct choice. The formula I = Es/R might seem plausible at first glance, but it assumes a different scenario involving the effective voltage drop across elements in an RC circuit, which can be misleading.

The ideal approach for determining the maximum current during the transient response in an RC circuit focuses on the values of voltage and resistance, reinforcing the use of Ohm's Law in this situation.