A 3.00 MΩ resistor and a 1.00 μF capacitor are connected in series with an ideal battery of emf E = 4.00 V. At 1.00 sec after the connection is made, what is the rate at which
(a) the charge of the capacitor is increasing;
(b) energy is being stored in the capacitor;
(c) thermal energy is appearing in the resistor; and
(d) energy is being delivered by the battery?
The Attempt at a Solution
About the only thing I can work out is that the time constant (R*C=3 seconds).
I'm not sure how I work out rate of charge. but I can't see how any of the formulas I've looked at mention any of these things. Surely they wouldn't expect me to differentiate these equations myself (professor is always saying he wants us to do physics, not maths). What am I missing?
I assume for (a) I need to find out the instantaneous current? So I=E/R e-t/RC
4/3MΩ * e-1/3 = 0.955μA
Do I just express that in coulombs?
Is (b) just another way of asking (a) - or is this talking about something different?
(c) I've yet to google , and (d) I assume takes into account (b) and whatever is lost in (c).
For now, help with (a) would be nice.
Last edited by a moderator: