Find the voltage across the resistor

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Homework Help Overview

The problem involves a circuit with a battery, internal resistance, and two resistors in series. The task is to determine the readings of an ammeter and a voltmeter in the circuit.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to calculate the current and voltage across a resistor but questions the accuracy of their voltmeter reading. Some participants emphasize the importance of showing work rather than just providing answers.

Discussion Status

Participants are actively discussing the calculations involved, with one providing a detailed approach to finding the total resistance and current. There is an ongoing exploration of the correct method to determine the voltmeter reading.

Contextual Notes

Participants are reminded of the forum's emphasis on showing work and reasoning in problem-solving, which may influence the responses and guidance offered.

ooohffff
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Homework Statement


A battery with
scriptE.gif
= 12.0 V and internal resistance r = 1.0 Ω is connected to two 6.9 kΩ resistors in series. An ammeter of internal resistance 0.50 Ω measures the current, and at the same time a voltmeter with internal resistance 10.0 kΩ measures the voltage across one of the 6.9 kΩ resistors in the circuit. What do the ammeter and the voltmeter read?

Homework Equations


V=IR

The Attempt at a Solution


So I found the ammeter reading where Itotal=1.09mA which was correct.
For the voltmeter reading, I got:
V=Itotal*6.9kΩ=7.52V which was incorrect. Anyone care to help?
 
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ooohffff said:
Anyone care to help?
Help what? You haven't shown any work, just answers. That's not the way it works here.
 
phinds said:
Help what? You haven't shown any work, just answers. That's not the way it works here.
Ammeter reading:
Rparallel=[(1/6.9k)+(1/10k)]-1=4082.84
Rtotal= 6.9kΩ+4082.84Ω+1Ω+.5Ω=10984.34Ω
Itotal=V/R=12/10984.34=.00109A

Better?
 
Ah, I got it it's V=ItotalRparallel
 

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