# Serial and Parallel AC Circuits Worksheet Question 9 Phase angle wrong

Discussion in 'Feedback and Suggestions' started by tjterblanche, Jun 10, 2009.

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1. ### tjterblanche Thread Starter Guest

The phase angle given as answer for Question 9 on the Series and Parallel Circuits worksheet seems to be wrong - should be -42.08 degrees?

2. ### t_n_k AAC Fanatic!

Mar 6, 2009
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I believe the answer given (-47.9 deg) is correct.

3. ### Wendy Moderator

Mar 24, 2008
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Show us your math, and why you think so, in the Electronics Chat area. You'll need to actually register, but you might find it interesting.

4. ### Dave Retired Moderator

Nov 17, 2003
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For the purposes of this query, I feel there is no need for the OP to register they can give feedback here in this thread.

I concur with t_n_k that the given answer is correct.

Dave

5. ### Wendy Moderator

Mar 24, 2008
20,772
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OK, my thought was we could go over his problem and help him work it out. Basically the open tutoring that is done around here.

6. ### tjterblanche Thread Starter Guest

Hi Bill,

Thanks for the reply, I appreciate it. And thanks for the e-book - it's a FANTASTIC resource.

I've taken the following steps in determining the phase difference:

1. Calculated XC (1 / (2 x PI x fC) = 1354.51ohm
2. Calculated the phase angle using trig: angle = atan Xc / R; answer was -42.082deg

I did note that if you do atan R/Xc, you get -47.91deg, but aren't you calculating the *outside* angle that way?

What am I missing?

Kind Regards,
Jaun

7. ### Wendy Moderator

Mar 24, 2008
20,772
2,540
Two things,

1. This forum is not for asking technical questions. Corrections to the books and worksheets are always appriciated, which is different.

2. Register, its free and painless. Then you can pick this up in the Electronics Chat forum, which is why it exists.

8. ### hgmjr Moderator

Jan 28, 2005
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This thread has run its course. I have locked it.

tjterblanche, I hope you will join the forum. Once you have joined, I'm sure the members will be more than happy to assist you with your questions.

hgmjr