When a DC source is removed abruptly from an RC circuit, the circuit becomes source-free. Assuming the fully charged capacitor's initial voltage is V0, its initial energy, which stimulates the circuit, can be obtained. Applying Kirchhoff's current law at the top node and substituting current values across the components gives a first-order differential equation. Rearranging terms, integrating, and taking the exponential on both sides, yields the natural response of the circuit, where the integration constant equals the initial voltage. The voltage versus time graph shows that the initial voltage decays exponentially with time. The time constant, tau, signifies the time required for the capacitor to discharge to 36.8 percent of its initial voltage. By substituting tau's value into the voltage response expression, the current and power dissipated in the resistor can be determined. Integrating the dissipated power over time provides the energy absorbed by the resistor. As the time approaches infinity, this energy approaches the initial energy stored in the capacitor, implying that the capacitor's initial energy gradually dissipates in the resistor.