Physics about electric circuits: Changing the resistors changes the currents

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Homework Help Overview

The discussion revolves around understanding electric circuits, specifically how changing resistors affects the currents within the circuit. Participants are exploring the relationships between resistance, current, and the application of Kirchhoff's laws.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster seeks assistance with their homework, indicating a lack of clarity in the problem. Some participants suggest redrawing the circuit for better visualization and organization of variables. Others mention the need for a list of equations that includes both Ohm's Law and Kirchhoff's rules, prompting questions about the poster's familiarity with these concepts.

Discussion Status

Participants are actively engaging with the problem, offering guidance on how to approach the circuit analysis. There is an emphasis on the necessity of organizing information and equations, but no consensus has been reached regarding the specific solution or methodology.

Contextual Notes

There is a mention of potential confusion regarding the values of resistance and the need for clarity in the problem statement. The original poster's understanding of Kirchhoff's laws is also questioned, indicating a possible gap in foundational knowledge.

blesssid
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New user has been reminded to always show their work on schoolwork problems.
Homework Statement
In an experiment with the circuit diagram as shown. Power source U = 1V; resistance R = 1Ω; Ammeters A1 and A2 are ideal ammeters (with zero resistance), and the currents through them can change when we change the value of the resistor r. Adjusting the value of the resistor r so that ammeter A2 shows 1A, ammeter A1 shows 3.5A. If we change the position between R1 and R2 and adjust the resistor r the A2 shows 1A, then A1 shows 7/3A .Calculate R1 and R2.
Relevant Equations
I = U/R
z5394064647850_0a06a36d985b29283c93c8b30763fd44.jpg

Please help me with this homework! I haven't had any solutions since it is all unclear.
 
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Unfortunately the PF rules do require you to post your best effort.
The least you can do is redraw the circuit so it looks more like something you can recognize and calculate...

[edit] to help you on your way: You have 2 situations, so you want to make a list of variables you are going to use to build a set of equations: e.g. two (unknown) values for ##r## means you need an ##r_1## and an ##r_2##. Four (known) currents means four variables like ##I_1, I_2, I_3, I_4##.

Your list of equations needs more than just Ohm with so many variables (think Kirchoff)

[edit] more help: with redrawing the circuit I mean something that has the battery on the left :rolleyes:

1714386180315.png
##\ ##
 
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Many thanks
 
blesssid said:
Relevant Equations: I = U/R
You will also need the equations of Kirchhoff's Loop Rule and Kirchhoff's Junction Rule.
Also, in the problem statement you have ##R=10##. I assume that's a typo and should be ##R=10\ \Omega##.

Have you covered Kirchhoff's Laws in your course?
 

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