Total Resistance of Parallel Circuit Calculation

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Homework Help Overview

The discussion revolves around calculating the total resistance of a parallel circuit involving three resistors with specified values. The original poster presents a calculation that appears to be incorrect and seeks assistance in determining the correct total resistance.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the arrangement of resistors, with one suggesting that R1 and R2 are in series before being combined in parallel with R3. There is also a question regarding the formula used by the original poster, as well as a correction about the value of R3.

Discussion Status

Some participants have provided guidance on how to approach the problem, including clarifying the arrangement of the resistors and correcting the resistor values. There is an acknowledgment of the original poster's misunderstanding of the formula, but no consensus on the final answer has been reached.

Contextual Notes

There is a discrepancy in the values provided for R3, with the original poster stating 18 ohms while another participant claims it is 13 ohms. Additionally, the original poster's answer was noted to be incorrect, and there is a requirement to express the final answer to one decimal place.

Vaish

Homework Statement


R1= 9 Ohms R2= 17 Ohms R3= 18 Ohms
what is the total resistance of this arrangement? Express answer in ohms, correct to one decimal place.

Homework Equations


I used the Parallel circuit formula 1/r1 + r2 + r3

The Attempt at a Solution


I got 4.0 Ohms, apparently, it is incorrect. Please help. Thank you!
 

Attachments

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R1 and R2 are in series, so use the series formula there.
Then the R1R2 resistors are in parallel with R3, so use the parallel formula with the series result and R3.

Also, in the graphic, R3 is 13 ohms, not the 18 you stated.
The "4.05" in the graphic is apparently your answer:
1) Although the problem asks for 1 decimal place, your answer is shown to two places.
2) Your answer is wrong. It is not 4.05 - it is substantially larger than that.
 
Thank you very much. This definitely helped and I also noted the 1 decimal place.
 
Vaish said:
1/r1 + r2 + r3
No such formula. What did you mean?
 

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