Electricity, Magnetism and Electromagnetism, Ch Ampère's law, magnetic flux and the shape of the magnetic field
Problem
Three long straight wires run perpendicular to the page and carry steady currents: wire 1 carries 9.0A into the page, wire 2 carries 4.0A out of the page and wire 3 carries 6.0A into the page. A closed loop drawn in the plane of the page encircles wires 1 and 2 only (wire 3 lies outside it) and is traversed clockwise, so that by the right-hand rule its positive normal points into the page.
((a)) Find the circulation ∮B⋅dl round this loop.
((b)) A flat circular coil of 120 turns and radius 3.0cm is placed in a uniform field of 0.25T with the plane of the coil at 25∘ to the field direction. Find the flux through one turn.
((c)) Find the flux linkage of that coil.