(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

When connected in series to a 110-V line, two resistors use one-fourth the power

that is used when they are connected in parallel. If one resistor is

2.0 kΩ, what is the resistance of the other?

2. Relevant equations

1/Rt = 1/R1 +1/R2 (total resistance in parallel)

Rt = R1 + R2 (resistance in series)

Power = Current x Voltage

3. The attempt at a solution

So far my attempts have fizzled, ending with negative numbers.

Heres what I did:

1) Set the two hypothetical circuits (series and parallel) equal to eachother by isolating the power:

P1 = 110^2/0.25(R1+R2)

P2 = 110^2(R1+R2)

And then isolating for R2 and solving (since we have R1 = 2000 ohms)

I ended up doing the quadratic equation and getting two negative numbers...

Any help would be appreciated :)

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# Homework Help: Finding an unknown resistance in an Electric Circuit

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