Question

Chapter 29, Problem 024 The figure shows, in cross section, four thin wires that are parallel, straight, and very long. They carry identical currents of i = 3.05 A in the directions indicated. Initially all four wires are at distance d = 11.1 cm from the origin of the coordinate system, where they create a net magnetic field B .(a) To what value of x must you move wire 1 along the x axis in order to rotate B counterclockwise by 30°? (b) With wire 1 in that new position, to what value of x must you move wire 3 along the x axis to rotate B by 30° back to its initial orientation? (a) Number (b) Number Units Units

Answer 1

Sol B = B₂ = By Bu в в M. I 29d B = Bit B2 + B₂ +By = But Bu = 24. I a (B, and B₂ cancel each other) 2nd @) fan er en is about - tan30" ma ca nu este 2nd . Bi-B₂ = I x 24. I VO 2nd 1-X = 215S > IX -1 = = 2.155 = 1- x = 0.464 X = 0.536 a = 5.998 cm wire 3 should also move by same autance Ta=5.948cm (6)