PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
A circuit consists of an ideal 9V battery, a switch S, a 3Ω resistor, and a 2.0mF capacitor connected in series. The capacitor is initially uncharged. At t=0 the switch is closed.
(a) Describe the behavior of the electric current in the circuit during the very first instant after the switch is closed. Include the physical reasoning that supports your description.
(b) Describe qualitatively how the current changes as time progresses from t=0 toward times much longer than any characteristic time of the circuit.
(c) Determine the value of the current in the circuit after a time that is much greater than the characteristic time of the circuit, and explain your reasoning with reference to the circuit elements.
(d) Compare the potential difference across the capacitor at t=0 and at t≫τ. Explain the physical basis for any difference you identify.