What is the voltage across the resistor?

1. Apr 19, 2013

JayLewis

1. The problem statement, all variables and given/known data

The amplitude of the voltage across an entire series circuit is 17 V. The inductor alone has an amplitude of 30 V and across the capacitor it is 22 V. To the nearest tenth, what is the voltage across the resistor?

2. Relevant equations

3. The attempt at a solution

(17+8i)(17-8i)

289+64
square root of 353
18.8

2. Apr 19, 2013

Staff: Mentor

Hello JayLewis, Welcome to Physics Forums.

Can you explain the reasoning behind your attempt?

3. Apr 20, 2013

JayLewis

I was trying to follow steps from handout

I was trying to follow steps from handout..this is the first time we have worked onthis and I don't understand it.

4. Apr 20, 2013

Staff: Mentor

Okay. I see that you're making use of complex numbers, so I assume that you're familiar with (or at least learning about) the concept of complex impedance and voltage and current. Is that right?

5. Apr 20, 2013

JayLewis

we are learning about it now

but the instructions aren't very clear

here is the rest of my work:

374-510i
_________
484+900

374-510i
_________
1384

.27-.37i
.07+.14
.21

6. Apr 20, 2013

Staff: Mentor

It's difficult to comment on your work since it's not annotated. What is it you're doing here?

If I may make a suggestion, suppose you consider the series RLC circuit being driven by a fixed AC current source. What would be the complex values of the potentials across the capacitor and inductor?

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