PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
Two uncharged capacitors, C1=5.0μF and C2=10μF, are connected in series with a 2.0MΩ resistor and a 20V ideal battery through an ideal switch S. At time t=0 the switch is closed, and current begins to flow.
(a) Determine the equivalent capacitance of the two–capacitor series combination.
(b) Calculate the time constant τ for the resulting RC circuit.
(c) At time t=τ, find the total charge stored on the series combination. Express your answer in microcoulombs.
(d) After a very long time has passed, the current in the circuit is effectively zero. Determine the potential difference across each capacitor in this final steady state.
(e) Compare the initial current immediately after the switch is closed to the current at time t=τ, and explain the physical reasons for the difference.