Physics Help: Electricity & Circuits

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SUMMARY

The discussion focuses on solving problems related to electricity and circuits, specifically calculating power dissipation in resistors and potential differences in series circuits. The user is tasked with finding the power dissipated by R3 in a series circuit with a 12V battery and three resistors: R1=45 ohms, R2=200 ohms, and R3=700 ohms. Key formulas mentioned include P=IV and P=I²R, emphasizing the importance of Ohm's Law and total resistance calculations to determine circuit current and voltage across resistors.

PREREQUISITES
  • Understanding of Ohm's Law
  • Familiarity with series circuit configurations
  • Knowledge of power equations in electrical circuits
  • Ability to calculate total resistance in series circuits
NEXT STEPS
  • Learn how to calculate total resistance in series circuits
  • Study the application of Ohm's Law in various circuit problems
  • Explore power dissipation calculations using P=IV and P=I²R
  • Practice finding potential differences across resistors in series circuits
USEFUL FOR

Students preparing for physics exams, educators teaching electricity concepts, and anyone looking to strengthen their understanding of circuit analysis and power calculations.

MJ
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I have a test tomorrow and I'm having trouble figuring out some of these review problems. Any help would be much appreciated!

1) Find the power dissipated by R3 in a series circuit with a 12V battery with 3 resistors. R1=45ohms R2=200ohms R3=700ohms

I also have a few questions where it asks you to find the potential difference between two points. For example, before and after a resistor in a circuit. How do i do this?

Thank you very much!
 
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Remember that P=IV

You have the total voltage, find the total resistsance. Then find how much voltage is used in R3.
 
Also, [itex]P=I^2R[/itex]. don't forget (or at least learn how to use Ohm's law) all of the power equations. Find total resistance. You should be able to find the circuit current then apply the above eq. Good luck on the test.
 

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