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In the given circuit, initially switch `S_(1)` is closed, and `S_(2)` and `S_(3)` are open. After charging of capacitor, at `t = 0`, `S_(1)` is opened and `S_(2)` and `S_(3)` are closed. If the relation between inductance, capacitance and resistance is `L = 4 CR^(2)`, tehn find the time (in s) after which current passing through capacitor and inductor will be same (given `R = In2 m Omega,L = 2 mH`) |
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Answer» Correct Answer - `(1)` After charging, charge on capacitor `= C epsilon` Now, at `t = 0` two circuits are formed 1. Discharging of capacitor `q = C epsilon e^(-t//tau_(C)) = Cepsilon e^(-t//RC)` `i_(1) = - (dq)/(dt) = (epsilon)/(2R) e^(-t//RC)` 2. Growth of current in `L - R` circuit. `i_(2) = (epsilon)/(2R) [1 - e^(-t//tau_(L))]` Now, `i_(1) = i_(2)` `(epsilon)./(2R) e^(-t//tau_(C)) = (epsilon)/(2R) [1 - e^(-t//tau_(L))]` ..(i) Given `l = 4CR^(2)` `(L)/(2R) = 2RC = (1)/(In 2) rArr tau_(C) = tau_(L) = (1)/(In 2)` Solve to get `t = 1 s` |
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