An inductor coil stores


An inductor coil stores $64 \mathrm{~J}$ of magnetic field energy and dissipates energy at the rate of $640 \mathrm{~W}$ when a current of $8 \mathrm{~A}$ is passed through it. If this coil is joined across an ideal battery, find the time constant of the circuit in seconds:

  1. $0.4$

  2. $0.8$

  3. $0.125$

  4. $0.2$

Correct Option: , 4


$\mathrm{U}=\frac{1}{2} \mathrm{Li}^{2}=64 \Rightarrow \mathrm{L}=2$

$i^{2} R=640$



Option (4)

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