From Ampere's circuital law for a long straight wire of cir…

Physics Moving Charge and Magnetism NEET Previous Year Question MCQ (Single Correct)

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 [NEET 2022]

a linearly increasing function of distance upto the boundary of the wire and then linearly decreasing for the outside region.

a linearly increasing function of distance

upto the boundary of the wire and then decreasing one with 1/r dependence for the outside region.

a linearly decreasing function of distance upto the boundary of the wire and then a linearly increasing one for the outside region.

uniform and remains constant for both the regions.

Text Solution

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The correct answer is:

According to Ampere's circuital law, magnetic field inside the current carrying long straight wire of circular cross-section is a linearly increasing function of distance upto the boundary of the wire and magnetic field outside the wire at distance from its axis is decreasing one with dependence as shown in figure.

where, R is radius of circular cross-section of wire.