# What is the voltage across the resistor?

## Homework Statement

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?

## The Attempt at a Solution

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

289+64
square root of 353
18.8

gneill
Mentor

## Homework Statement

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?

## The Attempt at a Solution

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

289+64
square root of 353
18.8
Hello JayLewis, Welcome to Physics Forums.

Can you explain the reasoning behind your attempt?

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.

gneill
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?

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

gneill
Mentor
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
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?