Question

Find the current I3.

A.

2.5 A

B.

1.5 A

C.

3.84 A

D.

1 A

Correct option is C

Using Kirchhoff’s Current Law (KCL):
The relationship between the currents is given as: ​I2=I3I1I_2 = I_3 - I_1

​​By applying Kirchhoff’s Voltage Law (KVL) in the left loop:
The equation becomes: 103I12I3=010 - 3I_1 - 2I_3 = 0

3I1+2I3=10... (a)3I_1 + 2I_3 = 10 \quad \text{... (a)}

​​By applying Kirchhoff’s Voltage Law (KVL) in the right loop:
The equation becomes: 4I2+2I3=204I_2 + 2I_3 = 20

4(I3I1)+2I3=204(I_3 - I_1) + 2I_3 = 20

4I1+6I3=20... (b)-4I_1 + 6I_3 = 20 \quad \text{... (b)}​       ​

Solving equations (a) and (b), the currents are:

I1=0.769 A, I2=3.071 A, I3=3.84 AI_1 = 0.769 \, \text{A}, \, I_2 = 3.071 \, \text{A}, \, I_3 = 3.84 \, \text{A}

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