Capacitors charged in parallel

AI Thread Summary
Capacitors C1 (6.97 uF) and C2 (1.54 uF) are charged in parallel across a 281 V battery, resulting in charges of approximately 1.5 mC for C1 and 0.5 mC for C2. After disconnecting from the battery, the capacitors are reconnected in series with opposite polarities. This configuration leads to a change in the effective voltage across each capacitor, which raises questions about the expected potential drop during the charging phase. The discussion clarifies that the battery provides the same potential drop only while the capacitors are charging in parallel, not after they are reconfigured. Understanding the charge distribution and voltage behavior in different configurations is crucial for solving capacitor problems.
L_landau
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Homework Statement


Capacitors C1 = 6.97 uF and C2 = 1.54 uF are charged as a parallel combination across a 281 V battery. The capacitors are disconnected from the battery and from each other. They are then connected positive plate to negative plate and negative plate to positive plate.
A) Calculate the resulting charge on capacitor C1.
B) Calculate the resulting charge on capacitor C2.

from this answer
http://www.chegg.com/homework-help/questions-and-answers/capacitors-c1-697-uf-c2-154-uf-charged-parallel-combination-across-281-v-battery-capacitor-q1385340

Homework Equations


Q = CΔV

The Attempt at a Solution


So q1 = 1.5x10-3c and q2 = 5x10-4c. Why would the drawing show opposite polarizations on the plates? Shouldn't the battery give the same potential drop across two capacitors in parallel?
 

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L_landau said:
from this answer
That answer is visible only to chegg members.
L_landau said:
Why would the drawing show opposite polarizations on the plates?
Because,
L_landau said:
They are then connected positive plate to negative plate and negative plate to positive plate.
 
But the picture is as they are charged and before they are connected positive to negative and vice-versa I thought?
 
L_landau said:
But the picture is as they are charged and before they are connected positive to negative and vice-versa I thought?
No. It is just after they are reconnected in series.

L_landau said:
Shouldn't the battery give the same potential drop across two capacitors in parallel?
That would be true when the capacitors were charging.
 
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