Tricky RC Circuit With Multiple Capacitors and Multiple Resistors

A circuit with two capacitors and two resistors is first charged with the switch closed at (a), and we have to find the charge on C2 after 70 micro seconds. Then the switch is opened at (a) and closed at (b) and we need to find the change on C2 after another 20 micro seconds.
Setting up the RC charging and discharging equation is complicated because there are multiple capacitors and resistors, and we need to be careful to only include the elements that are in the active circuit in each case.
Here's a related video demonstrating why charges in series will always have the same charge difference (also called "change in charge", or "delta Q"):
• Capacitors Charging in...
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www.redmondphysicstutoring.com....
Good luck!
Scott

[@s0hvaperuna]

It's great to see someone cover this problem with more than 1 capacitors since it was explained nowhere how the circuit behaves with more than 1 capacitor and it isn't always clear as to what to do

[@DarkOceanShark]

Yes you are right! No websites or books throw light on this case. I am glad I found this video

[@shivamdwivedi4283]

You made my concept crystal clear

[@zaidtamim]

This was 100% clear and straight to the point. Will be browsing through your videos for the rest of the semester. Great job

[@RedmondPhysicsTutoringVideo]

+zaidtamim
Fantastic - thank you for the feedback, and good luck with your course!

[@darkseid856]

Thanks ! This helped me alot :D

[@RedmondPhysicsTutoringVideo]

Glad to help! Good luck with your physics class!

[@AceofDlamonds]

Thanks. This type of problem is sooo annoying. For one, the textbook we are using is more like a reference book and I can't fully understand the concepts. Then they throw this type of problem at us and I cannot connect the dots!

[@amsu7445]

very nice keep going please

[@AnnuFzd]

What if the resistor is between the two capacitors? Will the equivalent resistance still be the same ?

[@RedmondPhysicsTutoringVideo]

Hmm.. That'll depend on how it's set up. You can count on Kirchoff's voltage and current laws. Good luck!

[@khaledtarek196]

I have a question how can i contact you to send it please!!