By how many volts is the battery 'loaded down'?

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Homework Help Overview

The discussion revolves around a battery with an emf of 24 volts and an internal resistance of 0.3 ohms, from which a current of 20 amperes is being drawn. Participants are exploring the concept of how the battery is "loaded down" in terms of voltage drop at the terminals during operation.

Discussion Character

  • Conceptual clarification, Assumption checking, Exploratory

Approaches and Questions Raised

  • Participants express uncertainty about the meaning of "loaded down" and its implications for battery voltage. There are inquiries into whether the voltage drop is dependent on the load resistance and discussions about how to interpret the relationship between emf, internal resistance, and current drawn.

Discussion Status

Some participants have provided clarifications regarding the term "loaded down" and its relation to the voltage at the battery's terminals. There is an ongoing exploration of how the voltage drop can be determined based on the given parameters, with acknowledgment of varying levels of understanding among participants.

Contextual Notes

Participants note that the expression "loaded down" may not be precise and that understanding the voltage drop requires consideration of the internal resistance and current drawn. There is a recognition that the problem's context may lead to different interpretations based on individual comprehension of the concepts involved.

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Battery "loaded down"?

Homework Statement



A current of 20 amperes is being drawn from a battery whose emf is 24 volts. The
internal resistance of the battery is 0.3 ohms. By how many volts is the battery "loaded
down"?


Homework Equations



V = IR

The Attempt at a Solution

I don't know what it means for the battery to be loaded down? Try searching for it but could not find anything. Please advice.
 
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a_patel32 said:

Homework Statement



A current of 20 amperes is being drawn from a battery whose emf is 24 volts. The
internal resistance of the battery is 0.3 ohms. By how many volts is the battery "loaded
down"?


Homework Equations



V = IR

The Attempt at a Solution

I don't know what it means for the battery to be loaded down? Try searching for it but could not find anything. Please advice.

Granted, "loaded down" is an inexact (perhaps colloquial) expression. In this case it refers to the amount by which the emf presented at the battery's terminals has fallen below its rated value.
 


Oh so after a battery has been used?
 


a_patel32 said:
Oh so after a battery has been used?
No, while it is being used.
 


Okay, I'm still unsure of how to solve this but I understand what you are saying so far, i think.
 


gneill said:
Granted, "loaded down" is an inexact (perhaps colloquial) expression. In this case it refers to the amount by which the emf presented at the battery's terminals has fallen below its rated value.

I'm kind of curious here. How much the emf at the terminals is below the rated value depends on what load you put on the battery right? So the "loaded down" voltage will be a function of the load resistance, right? Not a single number?
 


Dick said:
I'm kind of curious here. How much the emf at the terminals is below the rated value depends on what load you put on the battery right? So the "loaded down" voltage will be a function of the load resistance, right? Not a single number?

Indeed. Which is why the question asks, 'By how many volts is the battery "loaded
down"?' given a load drawing 20 A.
 
Last edited:


a_patel32 said:
Okay, I'm still unsure of how to solve this but I understand what you are saying so far, i think.

You have a 24V ideal voltage supply in series with 0.3 Ohms inside a box labelled "24V Battery". If a load that draws 20A is connected to this battery, what voltage will you "see" at the battery's terminals?
 


gneill said:
You have a 24V ideal voltage supply in series with 0.3 Ohms inside a box labelled "24V Battery". If a load that draws 20A is connected to this battery, what voltage will you "see" at the battery's terminals?

Is it necessary to calculate that? If "load down" refers to the amount by which the "usable" voltage has fallen, then they don't even need to provide the EMF of the cell, right? (given that they already stated the internal resistance and the current drawn)
 
  • #10


gneill said:
Indeed. Which is why the question asks, 'By how many volts is the battery "loaded
down"?' given load drawing 20 A.

Ooops. I missed that they gave you the current. Duh. Sorry. Carry on.
 
  • #11


Curious3141 said:
Is it necessary to calculate that? If "load down" refers to the amount by which the "usable" voltage has fallen, then they don't even need to provide the EMF of the cell, right? (given that they already stated the internal resistance and the current drawn)

How one gets to the answer depends upon one's understanding of the concepts. What is obvious to one may require a bit of "a-hah!" for another, particularly if it's early days studying a subject.

To answer your question, yes, you can determine the potential drop given the load current and the internal resistance. Whether or not this will be obvious or useful to the initial poster is another question :smile: Perhaps a_patel32 can comment.
 

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