Two long parallel wires are at a distance 2d apart. They carry steady equal current I flowing out of the plane of the paper. The variation of the magn - Physics MCQ AIEEE 2026 | ExamTest.live

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Two long parallel wires are at a distance 2 d apart. They carry steady equal current I flowing out of the plane of the paper. The variation of the magnetic field B along the line X X^{'} (perpendicular to wires) is zero at what point?

Solution & Step-by-step Explanation

Using the right-hand thumb rule, the magnetic fields produced by the two wires in the region between them are in opposite directions.Let the wires be at x = - d and x = + d .At the midpoint (x = 0), the distance to both wires is d . B_{1} = \frac{μ _{0} I}{2 π d} (directed up/down) B_{2} = \frac{μ _{0} I}{2 π d} (directed opposite)The net magnetic field B = B_{1} - B_{2} = 0 .The field is zero at the midpoint between the wires.

Try it yourself before checking the explanation above.

Two long parallel wires are at a distance 2 d apart. They carry steady equal current I flowing out of the plane of the paper. The variation of the magnetic field B along the line X X^{'} (perpendicular to wires) is zero at what point?

At the midpoint between the wires

At x = d /2

Nowhere between the wires

At the location of the wires

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