Five conductors meet at a junction P (see figure). Currents $I_1 = 2$ A and $I_3 = 5$ A flow **into** the junction, while $I_2 = 3$ A and $I_5 = 2$ A flow **out**. The current $I_4$ (direction: out of the junction) is: 
A2 A
B5 A
C1 A
D3 A
Answer & Solution
Correct answer: A. 2 A
KCL at P: arriving = leaving ⇒ $I_1 + I_3 = I_2 + I_4 + I_5$ ⇒ $2 + 5 = 3 + I_4 + 2$ ⇒ $I_4 = 2$ A.
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