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JEE Mains · Physics · STD 12 -6. Electromagnetic induction
An emf of \(20\; \mathrm{V}\) is applied at time \(\mathrm{t}=0\) to a circuit containing in series \(10\; \mathrm{mH}\) inductor and \(5 \;\Omega\) resistor. The ratio of the currents at time \(\mathrm{t}=\infty\) and at \(t=40\; s\) is close to : (Take \(e^{2}=7.389\) )
- A \(1.06\)
- B \(1.15\)
- C \(1.46\)
- D \(0.84\)
Answer & Solution
Correct Answer
(B) \(1.15\)
Step-by-step Solution
Detailed explanation
\(\mathrm{i}=\mathrm{i}_{0}\left(1-\mathrm{e}^{-\mathrm{R}t/ \mathrm{L}}\right)\) \(\frac{\mathrm{i}_{0}}{\mathrm{i}}=\frac{1}{1-\mathrm{e}^{-2 \times 10^{4}}}\) \(\frac{i_{0}}{i}=1\)
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