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In the circuit shown switch S is connected to position 2 for a long time and then joined to the position 1 . The total heat produced in resistance R 1 is :

Options

  1. ALE 2 2 R 2 2
  2. BLE 2 2 R 1 2
  3. CLE 2 2 R 1 R 2
  4. DLE 2 R 1 + R 2 2 2 R 1 2 R 2 2

Correct answer

A. LE 2 2 R 2 2

Step-by-step solution

When the key is at position (B) for a long time; the energy stored in the inductor is : U B = 1 2 Li 0 2 = 1 2 · L · E R 2 2 = LE 2 2 R 2 2 This whole energy will be dissipated in the form of heat when the inductor is connected to R 1 and no source is connected.

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