For the two cells having same EMF E and internal resistance r , the current passing through the external resistor 6 Ω is same when both the cells are connected either in parallel or in series. The value of internal resistance r is \ \ \ \ Ω .

Physics · Current Electricity

JEE Main 2026 — 28 January, Morning Shift — Question 33

For the two cells having same EMF E and internal resistance $r$ , the current passing through the external resistor $6 \Omega$ is same when both the cells are connected either in parallel or in series. The value of internal resistance $r$ is $\_\_\_\_$ $\Omega$ .

Option A:
3
Option B:
44
Option C:
9
Option D:
6
Correct

Answer: D

Step-by-step solution

In series, $i_{i}=\frac{2 E}{6+2 r}$ In parallel, $i_{2}=\frac{E}{6+\frac{r}{2}}$ $\mathrm{i}_{1}=\mathrm{i}_{2} \Rightarrow \frac{2 \mathrm{E}}{6+2 \mathrm{r}}=\frac{\mathrm{E}}{6+\frac{\mathrm{r}}{2}}$ $12+\mathrm{r}=6+2 \mathrm{r}$ $\mathrm{r}=6 \Omega$

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Exam: JEE Main 2026
Paper: 28 January, Morning Shift
Subject: Physics
Chapter: Current Electricity
Topic: Combination of Resistors and cells, Wheatstone Bridge

Answer: D

Step-by-step solution

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