Current Electricity 2 Question 7
7. In the given circuit diagram, the currents $I _1=-0.3 A$, $I _4=0.8 A$ and $I _5=0.4 A$, are
flowing as shown. The currents $I _2, I _3$ and $I _6$ respectively, are
(2019 Main, 10 Jan II)
(a) $1.1 A, 0.4 A, 0.4 A$
(b) $1.1 A,-0.4 A, 0.4 A$
(c) $0.4 A, 1.1 A, 0.4 A$
(d) $-0.4 A, 0.4 A, 1.1 A$
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Solution:
- Given circuit with currents as shown in the figure below, [In the question $I _1=0.3 A$ is given, due to it we change the direction of $I _1$, in this figure]
From Kirchoff’s junction rule, $\Sigma I=0$
$$ \begin{aligned} & \text { At junction } S, \quad I _4=I _5+I _3 \\ & \Rightarrow \quad 0.8=0.4+I _3 \\ & \Rightarrow \quad I _3=0.4 A \\ & \text { At junction } P, \quad I _5=I _6 \\ & \Rightarrow \quad I _6=0.4 A \\ & \text { At junction } Q, \quad I _2=I _1+I _3+I _6 \\ & =0.3+0.4+0.4=1.1 A \end{aligned} $$
