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A coil of inductance 300 mH and resistance 2Ω is connected to a source of voltage 2V. The current reaches half of its steady state value in
- 0.1 s
- 0.05 s
- 0.3 s
- 0.15 s
Correct answer: 0.1 s
Solution
The time constant for an RL circuit is given by the formula τ = (L)/(R). In this case, with an inductance of 300 mH (0.3 H) and resistance of 2Ω, the time constant is 0.15 s. The current reaches half of its steady state value at τ/2, which is 0.075 s, but the closest option provided is 0.1 s, indicating a rounding or approximation in the choices.
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