JEE Mains · Physics · STD 12 - 3. current electricity
A \(d.c.\) main supply of \(e.m.f.\, 220\, V\) is connected across a storage battery of \(e.m.f.\, 200\, V\) through a resistance of \(1\,\Omega \). The battery terminals are connected to an external resistance \('R'\) . The minimum value of \('R'\), so that a current passes through the battery to charge it is ............... \(\Omega\)
- A \(7\)
- B \(9\)
- C \(11\)
- D \(0\)
Answer & Solution
Correct Answer
(C) \(11\)
Step-by-step Solution
Detailed explanation
Given, \(emf\) of cell \(\mathrm{E}=200 \,\mathrm{V}\) Internal resistance of cells \(=1 \,\Omega\) D. C main supply voltage \(V=220\, \mathrm{V}\) External resistance \(\mathrm{R}=?\) \(r=\left(\frac{E-V}{V}\right) R\)…
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