# Kirchoff's Law Loop Equation Problem

This is the question I am struggling with I have found a node equation:

$$I_3 = I_1 + I_2$$

I have found two loop equations:

$$50 = I_3 + R_1 \times I_1$$

$$50 = I_3 + R_2 \times I_2$$

I'm not sure what the third loop equation is.

## 1 Answer

Your two loop equations are incorrect. I3 should not appear in either equation. For one, the units don't match: I3 is a current while R1*I1 and R2*R2 are voltages.Since your have 3 unknowns and 3 equations, a third loop equation is unnecessary. You could create a third loop equation using the loop around R1 and R2 but it does not yield any additional information about the unknown quantities: I1, I2 and I3.

• In that case, what would the loop equations be? I'm totally lost – Spartasporter Apr 22 '18 at 3:10
• So two of them would be: 50 = I2R2 and 50 = I1R1? – Spartasporter Apr 22 '18 at 3:16
• Yep @Spartasporter – Mitu Raj Apr 22 '18 at 5:47
• What would the third loop equation be then? – Spartasporter Apr 22 '18 at 6:07
• @Spartasporter You should read what Barry has written. "You could create a third loo...". – Harry Svensson Apr 22 '18 at 6:16