The combination of two identical cells, whether connected in series or parallel combination provides the same current through an external resistance of $2 \,\Omega$. The value of internal resistance of each cell is ............ $\Omega$
A$2$
B$4$
C$6$
D$8$
JEE MAIN 2022, Medium
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A$2$
a $I _{2}=\frac{ E }{\frac{ r }{2}+2}=\frac{2 E }{ r +4}$
$I _{1}= I _{2}$
$2 r +2= r +4$
$2 r - r =2 \,\Omega \Rightarrow r =2 \,\Omega$
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