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A choke coil has a self-inductance of 20 mH . If the magnetic potential energy stored in the coil is 90 mJ , what is the steady current passing through it?

Options

  1. A9 A
  2. B4.5 A
  3. C3 A
  4. D0.3 A

Correct answer

C. 3 A

Step-by-step solution

The magnetic potential energy U stored in an inductor of self-inductance L carrying a steady current I is given by the formula: U = 1 2 L I^2 Given: L = 20 mH = 20 10⁻³ H U = 90 mJ = 90 10⁻³ J Substituting the given values into the formula: 90 10⁻³ = 1 2 20 10⁻³ I^2 90 = 10 I^2 I^2 = 9 I = 3 A Answer: 3 A

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