Question

From Ampere’s circuital law for a long straight wire of circular cross-section carrying a steady current, the variation of magnetic field in the inside and outside region of the wire is:

• A. Uniform and remains constant for both the regions
• B. A linearly increasing function of distance up to the boundary of the wire and then linearly decreasing for the outside region
• C. A linearly increasing function of distance r up to the boundary of the wire and then decreasing one with 1/r dependence for the outside region
• D. A linearly decreasing function of distance up to the boundary of the wire and then a linearly increasing one for the outside region

Answer 1

Answer: (C)

A linearly increasing function of distance r up to the boundary of the wire and then decreasing one with 1/r dependence for the outside region

Answer 2

The correct option is (C): A linearly increasing function of distance r up to the boundary of the wire and then decreasing one with 1/r dependence for the outside region