Solving Resistance of a Wire: 21V Across 32m, 18m?

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Homework Help Overview

The problem involves a 32-meter length of resistive wire connected to a battery, with a voltmeter reading of 21 V across the battery terminals. The question asks what the voltmeter would read across an 18-meter section of the wire, requiring consideration of voltage distribution along the wire.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the relationship between the total voltage and the length of wire, with one participant suggesting that the voltage does not change, while others prompt for clarification on concepts related to series circuits and voltage drop.

Discussion Status

The discussion is ongoing, with participants seeking clarification on the principles of series circuits and the application of Ohm's Law. There is an exploration of how voltage drop occurs across different lengths of wire, but no consensus has been reached yet.

Contextual Notes

Participants are working under the constraint of not providing units in their answers and are encouraged to think about the problem in terms of individual segments of wire connected in series.

john216
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Homework Statement




Suppose that a 32-meter length of resistive wire is connected across the terminals of a battery. If a voltmeter reads 21 V when connected across the battery terminals, what should it read when connected across a 18-meter section of the wire? Enter you answers using one decimal place, do not enter units.



Homework Equations



e = iR


The Attempt at a Solution



thought the voltage doesn't change.
but I think its wrong. Please help?
 
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john216 said:

Homework Statement



Suppose that a 32-meter length of resistive wire is connected across the terminals of a battery. If a voltmeter reads 21 V when connected across the battery terminals, what should it read when connected across a 18-meter section of the wire? Enter you answers using one decimal place, do not enter units.

Homework Equations



e = iR

The Attempt at a Solution



thought the voltage doesn't change.
but I think its wrong. Please help?
Hello john216. Welcome to PF !

Think of this as 32 one-meter lengths of wire connected in series.

What is the voltage drop across anyone of those one-meter wires ?

How much across 18 of them ?
 
could you clarify little?
i'm confused
 
john216 said:
could you clarify little?
I'm confused
It's hard for me to know what part/parts of what I posted confuses you.

What do you understand about series circuits and resistances in series?

What do you understand about voltage drop and Ohm's Law?

etc.
 

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