JEE Mains · Physics · STD 12 - Current electricity
- JEE Mains 2021
- Hard
- Numerical
Five identical cells each of internal resistance \(1\, \Omega\) and \(emf \;5\, {V}\) are connected in series and in parallel with an external resistance \('R'.\) For what value of \('R',\) current in series and parallel combination will remain the same ? (in \(\Omega\))
Pick an option to check your answer.
Answer & Solution
Correct Answer
(A) \(1\)
Step-by-step Solution
Detailed explanation
\(i_{1}=\frac{25}{5+R}\)
\(i_{2}=\frac{5}{R+\frac{1}{5}}\)
\(i_{1}=i_{2} \Rightarrow 5\left(R+\frac{1}{5}\right)=5+R\)
\(4 R=4\)
\(R=1\, \Omega\)
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