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Physics - EMI/AC Question with Solution | TestHub

PhysicsEMI/ACL-R circuitHard2 minPYQ_2016

PhysicsHardsingle choice

The current in an $L - R$ circuit builds up to $(3/4)^{th}$ of its steady state value in 4 seconds. The time constant of this circuit is

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Solution:

$I = I_{0} (1 - e^{- t / τ})$ where $τ \to$ time constant $∴ \frac{3}{4} I_{0} = I_{0} (1 - e^{- t / τ}) \Rightarrow \frac{3}{4} = 1 - e^{- t / τ} \Rightarrow e^{- t / τ} = \frac{1}{4} \Rightarrow \frac{- t}{τ} ln e = ln \frac{1}{4} \Rightarrow \frac{- 4}{τ} = - 2 ln 2 \Rightarrow τ = \frac{2}{l n 2}$

Stream:VITEEESubject:PhysicsTopic:EMI/ACSubtopic:L-R circuit

⏱ 2mℹ️ Source: PYQ_2016

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