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Question 20175
JEE Physics · Medium

Magnetism: Ampere's Law — Long Wire MCQ

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Ampere's Law — Long WireMediumQuestion 20175

Question

Magnetic field at distance r from a long straight wire carrying current I is:
  1. A
    μ₀I/r
  2. B
    μ₀I/2πr
    Correct
  3. C
    μ₀I/4πr
  4. D
    μ₀Ir

Correct answer

μ₀I/2πr

Explanation

Applying Ampere's law along a circular path: B·2πr = μ₀I → B = μ₀I/(2πr).

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