# Homework Help: Finding current across capacitor

1. Jul 22, 2008

### kayak4life87

1. The problem statement, all variables and given/known data
An ac generator with a frequency of 30.0Hz and an rms voltage of 12.0V is connected to a 45.5uF capacitor. a) what is the maximum current in this circuit? b) what is the current in the circuit when the voltage across the capacitor is 5.25V and increasing? c) what is the current in the circuit when the voltage across the capacitor is 5.25V and decreasing?

2. Relevant equations
Irms=Vrms/Xc Xc=1/2pi(frequency)(capacitor) Io=Irms X square root of 2

3. The attempt at a solution

a) I first solved for Xc and got 116.6Ohms and Irms=12V/116.6Ohms=0.102A
Io=0.102X square root of 2=0.146A
I think i have this part right, but check it for me. thanks.

b) V=5.25V my attempt was to just divide by my Xc, but that does not come out right. the answer is the book is 138mA.

c) -138mA

thanks for the help

2. Jul 24, 2008

### Mindscrape

Part a) is good. I think you did parts b and c right too, is your book known to have errors?

3. Jul 24, 2008

### kayak4life87

very very rarely will it have a wrong answer...