The combination of two identical cells, whether connected in series or parallel combination provides the same current through an external resistance of 2 Ω. The value of internal resistance of each cell is :

Question

The combination of two identical cells, whether connected in series or parallel combination provides the same current through an external resistance of 2 Ω. The value of internal resistance of each cell is : (A) 2 Ω (B) 4 Ω (C) 6 Ω (D) 8 Ω

Tardigrade Admin · Accepted Answer

<img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/physics/9e98e459c9622a8a4f3cdc8005f6a2ed-.png" /> I 2=( E /( r )2+2)=(2 E / r +4) I 1= I 2 2 r +2= r +4 2 r - r =2 Ω ⇒ r =2 Ω

Q. The combination of two identical cells, whether connected in series or parallel combination provides the same current through an external resistance of $2 Ω$ . The value of internal resistance of each cell is :

$2 Ω$

$4 Ω$

$6 Ω$

$8 Ω$

$I_{2} = \frac{E}{\frac{r}{2} + 2} = \frac{2 E}{r + 4}$
$I_{1} = I_{2}$
$2 r + 2 = r + 4$
$2 r - r = 2 Ω$
$\Rightarrow r = 2 Ω$

Q. The combination of two identical cells, whether connected in series or parallel combination provides the same current through an external resistance of 2Ω. The value of internal resistance of each cell is :

2Ω

4Ω

6Ω

8Ω