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Question: Answered & Verified by Expert
An infinitely long hollow conducting cylinder with inner radius R/2 and outer radius R carries a uniform current density along its length. The magnitude of the magnetic field, B as a function of the radial distance r from the axis, is best represented by
PhysicsMagnetic Effects of CurrentJEE Main
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Solution:
2734 Upvotes Verified Answer
The correct answer is:

The required cylinder is shown in figure



Let j= current density, then

For, r<R2

B=0


For, R2rR

B×2πr=μ0r2-R24

B=μ0j2r-R24r


For, r>R

 B×2πr=μ0R2-R24

B=μ0j22R24r

B1/r [this is an equation for rectangular hyperbola.]

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