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NEETPhysicsMagnetic Effects of Current

An infinitely long hollow conducting cylinder with radius R carries a uniform current along its surface. Choose the correct representation of magnetic field B as a function of radial distance r from the axis of cylinder.

Correct answer

3

Step-by-step solution

According to Ampere's law, ∮ B → · d l → = μ 0 i Inside the hollow cylinder, current will be zero. Therefore, magnetic field will also be zero. Outside the cylinder, B 2 π r = μ 0 i ⇒ B = μ 0 i 2 π r ⇒ B ∝ 1 r Hence, the correct answer is D.

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