How Do You Find Frequency in an RC Circuit?

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RC Circuit, Finding Frequency? [Solved]

Solved =]

Homework Statement



Screenshot of an online quiz showing question 3 answered correctly with 15.3 ms, and question 4 answered incorrectly with 159 Hz, correct answer 6.7 Hz.


Homework Equations



Z = [ R2 + (1/wC)2 ]1/2
where Z is impedance, w = (omega) = angular frequency

Xc = 1/(wC)

w = 2(pi)f

(tau) = RC
where (tau) is the time constant

The Attempt at a Solution


I'm more confused than anything. Like I'm not sure what the set up is.
Two RC circuit schematics labelled A and B, separated by the word 'or' and a question mark: A has a resistor R in series with a capacitor C; B adds an AC voltage source on the left.


Just looking at the problem itself, the first part seems to give different numbers. When in the first part R = 4857.1 Ohms, and then in the second part R = 3629.6 Ohms?

At first I was working under the assumption that Z = R, but that would result in 0=1/(wC)
Then I googled impedance of the capacitor and some sources say that that is Xc, the capacitive reactance. So I solved R = Xc = 1/(wC) got that f = 1/ [ RC2(pi) ] , but when I tried plugging it in, I still couldn't get the answer that they have.EDIT:
Nevermind. I just figured it out. Turns out I was right for the frequency equation. I just used the numbers given instead in the second part and completely ignored the first part, and got the answer.

Um, how do I delete a thread?
 
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