2 Resistors in Parallel versus in Series

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SUMMARY

The discussion centers on calculating the resistance of a second resistor when two resistors are connected in series and parallel to a 110 V line. Given that one resistor is 2.0 kΩ, the other resistor's value is determined to be 1.56 kΩ. The power equations used include P=I²R and P=V²/R for series and parallel configurations. The calculations reveal that the power consumed in series is one-fourth that of the parallel configuration, confirming the relationship between resistance and power in different configurations.

PREREQUISITES
  • Understanding of Ohm's Law (V=IR)
  • Knowledge of power formulas (P=I²R and P=V²/R)
  • Familiarity with series and parallel resistor configurations
  • Basic algebra skills for solving equations
NEXT STEPS
  • Study the derivation of the equivalent resistance for resistors in series and parallel
  • Learn about power calculations in electrical circuits
  • Explore the quadratic equation and its applications in circuit analysis
  • Investigate the impact of resistor values on power consumption in different configurations
USEFUL FOR

Students in electrical engineering, hobbyists working with circuits, and anyone interested in understanding resistor behavior in series and parallel configurations.

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Homework Statement


Two resistors when connected in series to a 110 V line 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?


Homework Equations



V=IR

The Attempt at a Solution


v=ir

110=i(2000+x)

110=1/4(2000+x)

440=2000+x

x=440-2000

x=-1560

snce x= 1560

the value of another resistance is 1.56 kilo ohm

Did I do that right?
 
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Not quite. Okay, your series formula is fine. But now you have to get the power for the resistors in series. P=I^2 R and P=V^2/R.

Now that you have the power for the series resistors, find the power for the resistors if they were in parallel. 110=i*Req again, but different Req this time.
 
Can I just cancel the V's out and solve like this:

R2 + 2000 = 2*(2000*R2)/(2000 + R2)

Which looks like it would require the quadratic eqn
 

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