SATHEE: Electro Magnetic Induction And Alternating Currents Question 349

Electro Magnetic Induction And Alternating Currents Question 349

Question: The current in a LR circuit builds up to $\frac{3}{4}$ th of its steady state value in $4 s$ . The time constant of this circuit is [Roorkee 2000]

Options:

A) $\frac{1}{\ln 2} s$

B) $\frac{2}{\ln 2} s$

C) $\frac{3}{\ln 2} s$

D) $\frac{4}{\ln 2} s$

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Answer:

Correct Answer: B

Solution:

We know that $i = i_{o} [1 - e^{\frac{- R t}{L}}]$

or $\frac{3}{4} i_{o} = i_{o} [1 - e^{- t / τ}]$ (where $τ = \frac{L}{R} =$

time constant) $\frac{3}{4} = 1 - e^{- t / τ}$ or $e^{- t / τ} = 1 - \frac{3}{4} = \frac{1}{4}$

$e^{t / τ} = 4$

or $\frac{t}{τ} =$ ln 4
$\Rightarrow τ = \frac{t}{ln, 4} = \frac{4}{2, ln, 2} \Rightarrow, τ = \frac{2}{ln, 2} s e c .$

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Electro Magnetic Induction And Alternating Currents Question 349

Question: The current in a LR circuit builds up to $\frac{3}{4}$ th of its steady state value in $4 s$ . The time constant of this circuit is [Roorkee 2000]

Options:

Answer:

Solution:

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Electro Magnetic Induction And Alternating Currents Question 349

Question: The current in a LR circuit builds up to 34 th of its steady state value in 4s . The time constant of this circuit is [Roorkee 2000]

Options:

Answer:

Solution:

इंजीनियरिंग की तैयारी

चिकित्सा तैयारी

एनसीईआरटी पुस्तकें और समाधान

महत्वपूर्ण संसाधन

अन्य संसाधन

पाठ्यक्रम

परीक्षा मंच

नमूना मॉक टेस्ट

सदस्यता

एनसीईआरटी व्यायाम वीडियो समाधान

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Question: The current in a LR circuit builds up to $\frac{3}{4}$ th of its steady state value in $4 s$ . The time constant of this circuit is [Roorkee 2000]