Hi all, I'm new here, been havin' a good ol' tussle with this one. Has me frustrated because it seems pretty elementary.(adsbygoogle = window.adsbygoogle || []).push({});

1. The problem statement, all variables and given/known data

The circuit diagram has been drawn out in the attachment

The problem asks what is the current through the 20 ohm resistor.

2. Relevant equations

Parallel: 1/Req=1/R1+1/R2+...1/RN

Series: Req=R1+R2+...RN

I=V/R

3. The attempt at a solution

I've added the 10 and 5 ohm resistors to make 10/3 ohm to simplify that area of the diagram.

I've also added the 20 and 5 ohm resistors on the bottom end of the diagram to make 25 ohm.

Thus, adding these two equivalent resistances gives me 85/3. This leaves the resistor to the left of the battery.

Adding that one to this value as per the series rule of equivalent resistances gives me 115/3.

Using this equivalent resistance, I can find the total current, which comes out to be

I=25/(115/3)=75/115=.652 A.

From here, I am at a loss as to how to use this value to calculate the specific current at the 20 ohm resistor.

Am I even using the proper voltage to calculate the total current?

The correct answer to this problem is 227 mA.

Thanks, any help would be appreciated.

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# Homework Help: Resistance and Current-Direct Current Circuits

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