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Physics - EMI/AC Question with Solution | TestHub

PhysicsEMI/ACL-R circuitMedium2 minQB

PhysicsMediumsingle choice

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

Options:

Answer:

Solution:

Energy stored in an inductor, $U = \frac{1}{2} L I^{2}$
$\Rightarrow 64 = \frac{1}{2} L (8)^{2} \Rightarrow L = 2 H$
and power dissipated in a resistor, $P = I^{2} R$
$\Rightarrow 640 = (8)^{2} R \Rightarrow R = 10Ω$
Time constant of the $L R D C$ circuit is,
$τ = \frac{L}{R} = \frac{2}{10} = 0.2 s$

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

⏱ 2mℹ️ Source: QB

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