1. The problem statement, all variables and given/known data I have an RC circuit with two capacitors connected in parallel. Both capacitors are initially charged to 45.0 V. a.) How long after closing the switch S will the potential across each capacitor be reduced to 10.0V? Knowns: C1= 15.0 microFarads C2= 20.0 microFarads R1= 30.0 ohms R2= 50.0 ohms Here is a diagram. http://www.chegg.com/homework-help/...450--long-closing-switch-s-potential--q201797 2. Relevant equations v=q/c q=Q(initial)e^(-t/RC) 3. The attempt at a solution I know that both capacitors have the same potential difference because they are connected in parallel. I have used v=q/c to find the charge q of the first capacitor when the potential v is 10 V. q=vc =10V*(15*10^-6F) =1.5*10^-4C Next, I found the initial charge of the first capacitor.Q(initial) Q(initial)=45V*(15*10^-6F) =6.75*10^-4C Lastly, I foundthe time at which the potential of the first capacitor is 10V which corresponds to the charge q at that time. q=Q(initial)*e^(-t/RC) solving for time t=-RC*ln(q/Q(initial)) My answer comes out as 1.8 milliseconds but the correct answer is 4.21 milliseconds. Is there something wrong in my understanding of the problem? What is going on here?