Current Electricity Ques 29 — JEE PYQ Chapterwise

Answer:

Correct Answer: 29.(d)

Solution:

29. When the switch ’ $S$ ’ is closed the circuit, hence formed is given in the figure below,

Then, according to Kirchhoff’s current law, which states that the sum of all the currents directed towards a point in a circuit is equal to the sum of all the currents directed away from that point.

Since, in the above circuit, that point is ’ $C$ '

$\therefore i _1+i _2=i $

$\Rightarrow \frac{V _A-V _C}{2}+\frac{V _B-V _C}{4}=\frac{V _C-V}{2} $

$\text { or } \quad \frac{20-V _C}{2}+\frac{10-V _C}{4}=\frac{V _C-0}{2} $

$\Rightarrow 20-V _C+\left(10-V _C\right) 2=V _C $

$ 40=V _C+3 V _C $

$\text { or } \quad 40=4 V _C $

$\therefore \text { The current, } i=\frac{V _C}{2}=\frac{10}{2}=5$ $ A$