JEE Mains · Physics · STD 12 - 3. current electricity
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 ___________ \(\Omega\).
- A 3
- B 4
- C 9
- D 6
Answer & Solution
Correct Answer
(D) 6
Step-by-step Solution
Detailed explanation
In series, \(i_{1} = \frac{2E}{6+2r}\) In parallel, \(i_{2} = \frac{E}{6 + \frac{r}{2}}\) \(i_{1} = i_{2} \Rightarrow \frac{2E}{6+2r} = \frac{E}{6 + \frac{r}{2}}\) \(12+r = 6+2r\) \(\Rightarrow r = 6\Omega\)
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