Determine the magnitudes of the currents through R1 and R2 in (Figure 1) , assuming that each battery has an internal resistance r = 1.2 Ω .
Express your answers using two significant figures separated by commas.
Junction rule: I3 = I1 + I2 (any current going into one junction must come out with the same amount)
loop rule: The sum of all the potential differences around a complete loop is equal to zero.
The Attempt at a Solution
Please refer to the image I attached.
First I set up the directions for current flow. I got the equations:
I3 = I1 + I2.
For the top loop, I got -18*I2 - 22*I1 +9V = 0.
For the bottom loop, I got 6V + 18*I2 = 0. I isolated I2 to get -6/18 = -0.33333.
Then I plugged in I2(-0.33333) into the top loop's equation to isolate I1. I got I1 = 0.6818.
However, the masteringphysics keeps telling me it's wrong. Can anyone help me with this?
*I've randomly tried changing up the signs of the two numbers, which didn't work so I don't know where I went wrong.
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