2. Shown at right is a cross-sectional view of two long straight wires that are parallel to one another. One wire carries a current i, out of the page; the other carries an equal current i, into the page. a. Draw a vector on the diagram to show the direction of the magnetic field, if any, at point P. Explain your reasoning. b. Suppose that a third wire, carrying another current i, out of the page, passes through point P. Draw a vector on the diagram to indicate the magnetic force, if any, exerted on the current in the new wire at P. If the magnitude of the force is zero, indicate that explicitly. Explain your reasoning. c. Suppose instead that the third wire (carrying the same current i, out of the page) is placed such that the magnetic field at point P has zero magnitude. Determine the location of the third wire. (Hint: You will need to know how the magnetic field depends on the distance from the wire. This relationship can be found in your text.) Clearly indicate on the diagram at right the correct location of the new wire. Explain how you determined your answer. i O= out of the page i i Oi. P O-i. 12.0 into the page New wire at point P O-i. P

2. Shown at right is a cross-sectional view of two long straight wires that are parallel to one another. One wire carries a current i, out of the page; the other carries an equal current i, into the page. a. Draw a vector on the diagram to show the direction of the magnetic field, if any, at point P. Explain your reasoning. b. Suppose that a third wire, carrying another current i, out of the page, passes through point P. Draw a vector on the diagram to indicate the magnetic force, if any, exerted on the current in the new wire at P. If the magnitude of the force is zero, indicate that explicitly. Explain your reasoning. c. Suppose instead that the third wire (carrying the same current i, out of the page) is placed such that the magnetic field at point P has zero magnitude. Determine the location of the third wire. (Hint: You will need to know how the magnetic field depends on the distance from the wire. This relationship can be found in your text.) Clearly indicate on the diagram at right the correct location of the new wire. Explain how you determined your answer. i O= out of the page i i Oi. P O-i. 12.0 into the page New wire at point P O-i. P