EMF, Power Output, and Terminal Voltage

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SUMMARY

The discussion focuses on calculating the electromotive force (emf), total power output, and terminal voltage of a battery supplying a steady current of 5.6 A for 21 seconds. The battery transforms 1410 J of chemical energy into electric energy, with 560 J dissipated as heat. The emf is determined using the formula emf = (1410 J - 560 J) / (21 s) multiplied by the charge per coulomb. The total power output is calculated using P = VI, and the terminal voltage is derived from the relationship between emf and internal resistance.

PREREQUISITES
  • Understanding of electromotive force (emf) and its calculation
  • Familiarity with electrical power equations (P = VI)
  • Knowledge of energy transformations in electrical systems
  • Basic concepts of internal resistance in batteries
NEXT STEPS
  • Study the derivation of the emf formula in electrochemistry
  • Learn about internal resistance and its impact on terminal voltage
  • Explore the relationship between power output and energy efficiency in batteries
  • Investigate advanced battery management systems for optimizing performance
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Students in physics or electrical engineering, battery technology enthusiasts, and professionals involved in energy management and optimization of battery systems.

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Homework Statement


A battery supplies a steady current of 5.6 A for 21s. During this time 1410J of chemical energy is transformed into electric energy, but 560J of this electric energy is transformed into heat energy inside the battery.

a) What is the emf of the battery?

b) What is the total power output of the battery?

c) What is the terminal voltage fo the battery?


Homework Equations


emf= Ve + V
P= VI or P= V2/R
Ve= emf - V or Ve= emf- Ir

The Attempt at a Solution


My attempt to find the emf was (1410J)/(21s) and to multiply that by (1.6 X 10-19), since the emf is the "amount of chemical energy transformed to electric potential energy per coulomb of charge." However, I am not sure if I am to include or minus the 560J from the 1410J.
Then to find the power output, I am assuming that you would use P=VI, where the V is the emf.
After that, I don't know how to find the terminal voltage.
 
Physics news on Phys.org
Looks like you just stuck the charge of a single electron in there. You know P=VI, and you know power is just a rate of energy, P = E/t. That means you have everything you need.
 

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