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NEETPhysicsElectromagnetic Induction

An inductor stores 25 mJ of magnetic energy when a steady current of 5 A flows through it. What is the inductance of the inductor?

Options

  1. A2 mH
  2. B1 mH
  3. C5 mH
  4. D10 mH

Correct answer

A. 2 mH

Step-by-step solution

The magnetic energy U stored in an inductor is given by the formula: U = 1 2 L i^2 Rearranging the formula to solve for inductance L : L = 2U i^2 Substitute the given values ( U = 25 10⁻³ J and i = 5 A ): L = 2 25 10⁻³ 5^2 L = 50 10⁻³ 25 L = 2 10⁻³ H = 2 mH Using the incorrect formula L = U i^2 gives 1 mH , and forgetting to square the current yields 10 mH or 5 mH . Answer: 2 mH

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