Solving for Terminal Voltage and Current in a Battery Circuit

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Homework Help Overview

The discussion revolves around calculating the terminal voltage and current in a battery circuit, specifically involving a battery with internal resistance and an external resistor. The subject area includes concepts of electrical circuits and Ohm's law.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss using the formula V = E - Ir to account for internal resistance. There are questions about how to determine the total circuit current and the impact of voltage drop across the internal resistance on terminal voltage.

Discussion Status

Some participants have provided guidance on treating internal resistance as a series resistor and calculating net resistance. However, there remains some confusion regarding the implications of these calculations on terminal voltage.

Contextual Notes

Participants are navigating the relationship between terminal voltage, internal resistance, and external load resistance, with some expressing uncertainty about the calculations involved.

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A battery has a terminal voltage of 12.0 V when no current flows. Its internal resistance is 2.0 Ω. If a 1.7 Ω resistor is connected across the battery terminals, what is the terminal voltage and what is the current through the 1.7 Ω resistor?


Can someone point me in the right direction?
I know I have to use V = E - Ir because there is a internal resistance.
But I am not sure how to start...

Thanks in advance.
 
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Treat the internal resistance as a series resistor, find the total circuit current.

What is the voltage drop across the internal resistance? What do you think that will do to the terminal voltage?
 
The terminal voltage is less than the emf because there is a voltage drop across the internal resistance.

I am still confused.
 
Last edited:
As said earlier treat internal resistance as a series resistor

net resistance= R+r = 2+1.7

current= E/R = 12/3.7

terminal voltage = E - Ir
 
thank you so much!
 

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