GATE 2022 EC – Question 13

Networks, Signals and Systems · Circuit Analysis · 1 mark · Multiple choice

The current $I$ in the circuit shown is ________.

$1.25\times10^{-3}$ A
$0.75\times10^{-3}$ A
$-0.5\times10^{-3}$ A
$1.16\times10^{-3}$ A

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Correct answer: (B) $0.75\times10^{-3}$ A

Explanation

Let $V_A$ be the middle node voltage. The current source forces 1 mA through the right 2 kΩ towards the node, so KCL at A gives $\frac{5-V_A}{2\text{k}}+1\text{ mA}=\frac{V_A}{2\text{k}}$. Hence $5-V_A+2=V_A$, $V_A=3.5$ V and $I=\frac{5-3.5}{2\text{k}}=0.75$ mA.