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

Answer 1

Answer: (D)

Correct answer is (d) a linearly increasing function of distance $r$ upto the boundary of the wire and then decreasing one with $1 / r$ dependence for the outside region.