Answer Happy

V REF L Top View

A metal conducting rod is free to move along horizontal conducting tracks connected at one end by a wire and a resistor of resistance R, as shown above. The tracks are a distance L apart. The rod is pulled to the right with force F so it moves at a constant speed v. There is a uniform magnetic field of unknown magnitude B perpendicular to the plane of the page. Students measure R, L, F, and v. Which of the following properties, if any, of the magnetic field can the students determine? A The magnitude of the field can be determined, but not the direction because the direction of the current in the loop cannot be determined. The direction of the field can be determined, but not the magnitude because the value of the current in the loop is not known. Both the magnitude of the field and its direction can be determined because enough information is given. D Neither the magnitude nor the direction of the magnetic field can be determined.