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3. current electricity — Physics STD 12 Science — Question

CBSE BoardEnglish MediumSTD 12 SciencePhysics3. current electricity1 Mark
MCQ
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 ............ $\Omega$
  • ✓
    $2$
  • B
    $4$
  • C
    $6$
  • D
    $8$
✓

Answer

Correct option: 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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