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NEET2015PhysicsMagnetic Effects of CurrentActual

An electron moving in a circular orbit of radius r makes n rotations per second. The magnetic field produced at the center has magnitude:

Options

  1. Aμ 0 n e 2 π r
  2. BZero
  3. Cμ 0 n 2 e r
  4. Dμ 0 n e 2 r

Correct answer

D. μ 0 n e 2 r

Step-by-step solution

If an electron is doing n revolutions per second then we can say the current is, i = q T = e T     we know that   T = 1 n . ⇒ i = e T = n e Now, magnetic field at the center of a circular loop is B = μ 0 i 2 r = μ 0 n e 2 r

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