## Finding Terminal Voltage

1. The problem statement, all variables and given/known data
In the circuit shown in the figure below the current through the 12.0V battery is measured to be 70.6 mA in the direction shown. What is the terminal voltage Vab

2. Relevant equations
V=E-IR
I1=I2+I3

3. The attempt at a solution
First I set Vab= E-IR= 24 - 10(I1)
I1=I2 + I3
So I applied Kirchoff's rule on the outer loop to find I3
-12 - 10I2 + 20I3 = 0
I3= [12 + 10I2]/20 = 0.6000353 = 0.6A
I1= I2 + I3 = 70.6 mA + 0.6A = 0.6000706A = 0.6A
Vab= 24 -10I1 = 24 - 6 = 18V
Is this right?
Attached Images
 Circuit.bmp (96.1 KB, 26 views)
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 Recognitions: Gold Member Homework Help Science Advisor Staff Emeritus What happened to the 30-ohm resistor? The voltage due to the internal resistance of the 12-volt battery is (70.6 mA)(10 ohms) = 706 mV = 0.706 V. You seem to have divided by another factor of 1000.
 Can I combine the 20(ohm) with the 10(ohm) resistor?

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