Find EMF of a battery in this circuit

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SUMMARY

The discussion focuses on calculating the electromotive force (EMF) of a battery in a circuit involving two batteries in parallel. Participants emphasize the importance of simplifying the circuit to derive numerical answers, specifically using Kirchhoff's Voltage Law (KVL) to find the unknown EMF. One user mentions obtaining an equivalent resistance of 98.9 ohms, prompting inquiries about its accuracy. The conversation highlights the necessity of drawing circuit configurations accurately to facilitate calculations.

PREREQUISITES
  • Understanding of Kirchhoff's Voltage Law (KVL)
  • Basic circuit analysis techniques
  • Familiarity with parallel battery configurations
  • Ability to calculate equivalent resistance
NEXT STEPS
  • Learn how to apply Kirchhoff's Voltage Law (KVL) in complex circuits
  • Study the principles of simplifying circuits with parallel components
  • Explore methods for calculating equivalent resistance in mixed circuits
  • Investigate the impact of battery configurations on overall circuit performance
USEFUL FOR

Electrical engineering students, circuit designers, and hobbyists interested in battery circuit analysis and simplification techniques.

jdmaxwell02
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Homework Statement
In the circuit below R=53.0 Ω and assume both batteries have zero internal resistance and the voltmeter and ammeter are ideal. When the switch is open the voltmeter displays 14.2 V.



Find the emf e m f of the unknown battery: ___ V

If the switch is closed what does the ammeter display? ____ A
Relevant Equations
EMF-Ir=IR?
1585098373348.png
 

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why did you stop where you did in simplifying the circuit?

EDIT: oh, wait ... I see now. You didn't simplify the circuit at all, you drew the two cases.

Simplify the circuit in each case and you can work it down to numerical answers.
 
phinds said:
why did you stop where you did in simplifying the circuit?

EDIT: oh, wait ... I see now. You didn't simplify the circuit at all, you drew the two cases.

Simplify the circuit in each case and you can work it down to numerical answers.

The two batteries in parallel are kinda confusing me. How would I simplify that? Also, I got 98.9 for the equivalent Resistance. Does that seem correct?
 
jdmaxwell02 said:
The two batteries in parallel are kinda confusing me. How would I simplify that?
First, draw the circuit when the switch is open. With that information, can you find the unknown emf using KVL?
 
Last edited:

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