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JEE Advanced 2022
Paper-1 2022
Multiple correct answers - Select all that apply
Question
The figure shows a circuit having eight resistances of $1 \Omega$ each, labelled $\mathrm{R}_1$ to $\mathrm{R}_8$, and two ideal batteries with voltages $\varepsilon_1=12 \mathrm{~V}$ and $\varepsilon_2=6 \mathrm{~V}$.

Which of the following statement (s) is (are) correct?
Select ALL correct options:
A
The magnitude of current flowing through $R_1$ is 7.2 A .
B
The magnitude of current flowing through $R_2$ is 1.2 A .
C
The magnitude of current flowing through $R_3$ is 4.8 A .
D
The magnitude of current flowing through $R_5$ is 2.4 A .
✓ Correct! Well done.
✗ Incorrect. Try again or view the solution.
⚠ Partially correct. Some answers are missing.
Solution

Point A and B are at same potential so they can be merged/folded.

For loop 1
$ \begin{aligned} & -\frac{1}{2} x-\frac{1}{2}(x+y)-x+6=0 \\ & -2 x-\frac{y}{2}=-6 \\ & -4 x-y=-12 \\ & 4 x+y=12 \end{aligned} $
For loop 2
$ \frac{1}{2} y+1 y+12+\frac{1}{2}(x+y)=0 $
$ \begin{aligned} & \frac{3}{2} y+\frac{y}{2}+\frac{x}{2}=-12 \\ & 2 y+\frac{x}{2}=-12 \\ & 4 y+x=-24 \\ & 4 y+x-16 x-4 y \\ & =-24-48 \\ & -15 x=-72 \\ & x=\frac{72}{15} \\ & 4\left(\frac{72}{15}\right)+y=12 \\ & y=12-\frac{288}{15} \\ & =\frac{180-288}{15}=\frac{-108}{15}=-7.2 \mathrm{~A} \end{aligned} $
Current in $\mathrm{R}_1=7.2 \mathrm{~A}$
Current in $R_2=\frac{x+y}{2}=\left(\frac{72}{15}-\frac{108}{15}\right) \frac{1}{2}$
$ \begin{aligned} & \frac{1}{2}\left(\frac{36}{15}\right)=\frac{2.4}{2} \mathrm{~A} \\ & =1.2 \mathrm{~A} \end{aligned} $
Current in $\mathrm{R}_3=\mathrm{x}=4.8 \mathrm{~A}$
Current in $\mathrm{R}_5=\frac{1}{2} \mathrm{x}=2.4 \mathrm{~A}$
Question Tags
JEE Advance
Physics
Easy
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