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In the given circuit the switch is closed at t = 0, and the ammeter current versus time follows the displayed graph (a critically/over-damped LCR transient). With C = 4 microfarad and L = 0.1 mH, the condition shown corresponds to critical damping. Find the value of R (in ohm).
- 10 ohm
- 5 ohm
- 20 ohm
- 2.5 ohm
Correct answer: 10 ohm
Solution
Critical damping in a series LCR circuit occurs when R = 2*sqrt(L/C). The graph (no oscillation, fastest non-overshoot decay) indicates critical damping, so substituting the given L and C yields R. (The graph's qualitative shape is reconstructed to allow a self-consistent numeric answer.)
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