Just provide the answer with a simple few words explanation or provide the equation if relevant:

42. Which graph correctly gives the magnitude of the magnetic field outside an infinitely long, very thin, straight current-carrying wire as a function of the distance from the wire? L L B B A) 1 B) II C) III D) IV E) V 43, The magnetic field a distance 2 cm from a long straight current-carrying wire is 2 x 10 T. The current in the wire is: A) 0.16 A B) 1.0A C) 20A D) 40A E) 25A 44. Lines of the magnetic field produced by a long straight wire carrying a current are: A) in the direction of the current B) opposite to the direction of the current C) leave the wire radially D) circles concentric with the wire E) lines similar to those produced by a bar magnet 39. The diagrams show five possible orientations of a magnetic dipole 4 in a uniform magnetic field B. For which of these does the magnetic torque on the dipole have the greatest magnitude? i 7 2 Z Z +F F A=F NF F | I 1l IV W A) 1 B) II C) II D) IV E) V 40. The diagrams show five possible orientations of a magnetic dipole j in a uniform magnetic field B. For which of these is the potential energy the greatest? 4 e L M 4 %E' =F AF F F I 1 1]l N W A) 1 B) II C) III D) IV E) V 41. Electrons are going around a circle in a counterclockwise direction as shown. At the center of the circle they produce a magnetic field that is: electmn A) into the page B) out of the page C) to the left D) to the right E) zero 37. An electron and a proton both each travel with equal speeds around circular orbits in the same uniform magnetic field, as shown in the diagram (not to scale). The field is into the page on the diagram. Because the electron is less massive than the proton and because the electron is negatively charged and the proton is positively charged: 0:( ) A) the electron travels clockwise around the smaller circle and the proton travels counterclockwise around the larger circle. B) the electron travels counterclockwise around the smaller circle and the proton travels clockwise around the larger circle C) the electron travels clockwise around the larger circle and the proton travels counterclockwise around the smaller circle D) the electron travels counterclockwise around the larger circle and the proton travels clockwise around the smaller circle E) the electron travels counterclockwise around the smaller circle and the proton travels counterclockwise around the larger circle 38. The diagram shows a straight wire carrying a flow of electrons into the page. The wire is between the poles of a permanent magnet. The direction of the magnetic force exerted on the i AT B) C) D) E) into the page