Figure 29-49 shows two very long straight wires (in cross section) that each carry a current of$\mathbf{4}\mathbf{.}\mathbf{00}\mathbf{}\mathbf{A}$ directly out of the page. Distance ${\mathbf{d}}_{\mathbf{1}}\mathbf{=}\mathbf{}\mathbf{6}\mathbf{.}\mathbf{00}\mathbf{}\mathbf{m}$ and distance ${\mathbf{d}}_{\mathbf{2}}\mathbf{=}\mathbf{4}\mathbf{.}\mathbf{00}\mathbf{}\mathbf{m}$. What is the magnitude of the net magnetic field at point P, which lies on a perpendicular bisector to the wires?

Figure 29-68 shows two closed paths wrapped around two conducting loops carrying currents ${\mathit{i}}_{\mathbf{1}}\mathbf{=}\mathbf{}\mathbf{5}\mathbf{.}\mathbf{0}\mathbf{}\mathit{A}$ and ${\mathit{i}}_{\mathbf{2}}\mathbf{=}\mathbf{}\mathbf{3}\mathbf{.}\mathbf{0}\mathbf{}\mathit{A}$. (a) What is the value of the integral $\mathbf{\oint }\overrightarrow{\mathbf{B}}\mathbf{}\mathbf{.}\overrightarrow{\mathbf{d}\mathbf{s}}$ for path 1 and (b) What is the value of the integral for path 2?

A long wire carrying 100A is perpendicular to the magnetic field lines of a uniform magnetic field of magnitude 5.0 mT. At what distance from the wire is the net magnetic field equal to zero?

A current is set up in a wire loop consisting of a semicircle of radius$\mathbf{4}\mathbf{.}\mathbf{00}\mathbf{}\mathbf{cm}$, a smaller concentric semicircle, and two radial straight lengths, all in the same plane. Figure 29-47a shows the arrangement but is not drawn to scale. The magnitude of the magnetic field produced at the center of curvature is $\mathbf{47}\mathbf{.}\mathbf{25}\mathbf{}\mathbf{\mu T}$. The smaller semicircle is then flipped over (rotated) until the loop is again entirely in the same plane (Figure29-47 b).The magnetic field produced at the (same) center of curvature now has magnitude $\mathbf{15}\mathbf{.}\mathbf{75}\mathbf{}\mathbf{\mu T}$, and its direction is reversed. What is the radius of the smaller semicircle.

Figure 29-26 shows four arrangements in which long parallel wires carry equal currents directly into or out of the page at the corners of identical squares. Rank the arrangements according to the magnitude of the net magnetic field at the center of the square, greatest first.

Figure shows a cross section of a long thin ribbon of width $\mathbf{w}\mathbf{=}\mathbf{4}\mathbf{.}\mathbf{91}\mathbf{cm}$ that is carrying a uniformly distributed total currentlocalid="1663150167158" $\mathit{i}\mathbf{=}\mathbf{4}\mathbf{.}\mathbf{16}\mathit{m}\mathit{A}$ into the page. In unit-vector notation, what is the magnetic field at a point P in the plane of the ribbon at a distance localid="1663150194995" $\mathit{d}\mathbf{=}\mathbf{2}\mathbf{.}\mathbf{16}\mathit{c}\mathit{m}$ from its edge? (Hint: Imagine the ribbon as being constructed from many long, thin, parallel wires.)