What is the total power of all of the resistors on the picture?
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On the picture above, I have assumed the directions of the currents I 1 , I 2 , and I . Using Kirchoff's First Law, we can see that I = I 1 + I 2 . I have also marked points A and B. We can see that they have the same potentials, meaning that U a b = 0 . U a b can also be expressed as E − E − R ∗ I 2 − R ∗ I 1 , meaning that I_1 = I_2 = \(\frac{I}{2} ). U a b can also be expressed as E − R ∗ I − R ∗ I 1 + E . Switching I with \(\frac{I_1}{2} ) gives us an equation from which we can express I 1 as \(\frac{2E}{3R} ), and that is also equal to I 2 . The total power is equal to the sum of all of the powers on the resistors, and is equal to 2*R*I_1^2 + R*I^2 = \(\frac{8E^2}{3R} ).