A 7.50 F capacitor, C1, is initially connected to a 90.0 V battery and is given a charge Q. The capacitor is disconnected from the battery and then connected to an initially uncharged capacitor, C2. Assume the two capacitors are connected such that the positive plates of each are connected and the negative plates of each are connected. The voltage across both capacitors C1 and C2 drops to 12 V after they are connected.
a. What is the initial charge on capacitor C1?
b. What are the charges on capacitors C1 and C2?
c. What is the capacitance of capacitor C2?
The Attempt at a Solution
q=675 C ok, this one was easy
but I'm stuck in part b of the question. Will the charges be the same or not?
This is what I'm trying to do:
q1 + q2 = (7.5 + C_2)12
675 + q2 = 90 + 12C_2