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Pd accross capacitance

  • #1

Homework Statement


upload_2015-2-3_22-46-50.png


Find the pd accros C2

Homework Equations


Q=CV

The Attempt at a Solution


i find C23 = (C2C3)/ (C2 + C3)
then find Q23 = V x C23
Q23 = Q2 = C2V2 => V2

i used this and got V2 = 15V , however the answer is 20V , and i even didnt use the data of C1 . am i wrong somewhere ?
 

Answers and Replies

  • #2
gneill
Mentor
20,714
2,715
Your answer looks fine, unless there are some initial conditions (such as initial charges) that weren't specified. C2 and C3 form a voltage divider which is across the supply 30 V, and since they are of equal capacitance they must must divide the voltage.... how?
 

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