What is the entropy change of the universe as a result of the following processes:
(a) a 1μF capacitor is connected to a 100V electrochemical cell at 0°C,
(b) the same capacitor after being charged to 100V is discharged through a resistor kept at 0°C?
dS = δQ/T (for reversible processes)
dS > δQ/T (for irreversible processes)
Capacitor energy = ½*C*V^2
The Attempt at a Solution
The main thing I'm stuck on is what exactly is happening at (a). I'm not quite sure where the entropy change could come from, or what could cause it. It seems to me that there isn't enough information - are they asking for the entropy change at the instant the capacitor is connected, in which case there's been no current flow, and so has anything actually happened? Are we meant to consider the work done in physically connecting the capacitor? (I would doubt so.) If it is at the instant when they are connected, before any current has flowed, then either nothing has happened, or it's fully reversible (both of which would give ΔS = 0), or we have no idea what the entropy change is because it's to do with the work done getting it there.
As for (b), if we say the capacitor energy is equal to the heat, then ΔS =(C*V^2)/(2*T) = 1.83x10^(-5), but I'm not sure if this is for just the capacitor or if this is the change in entropy of the universe? I'm not sure exactly what angle to approach this from, but that's my main guess at how I'd go forward, but it might be wrong.
I'd really appreciate any thoughts on part (a) of the question - if I've missed anything especially, and also maybe some hints on how to proceed on part (b) (and if I'm going in the right direction or not). Can't seem to find examples of similar questions online either! (If you know of any, please link me!)