Magnetic levitation A metal rod of length w = 11 cm and mass m = 90 grams has metal loops at both ends, which go around two metal poles (see the figure). mmass of rod W The rod is in good electrical contact with the poles but can slide freely up and down. The metal poles are connected by wires to a battery, and a current I = 2 amperes flows through the rod. A magnet supplies a large uniform magnetic field B in the region of the rod, large enough that you can neglect the magnetic fields due to the 2 ampere current. The large magnetic field is oriented to have the maximum effect. The rod floats at rest h = 6 cm above the table. What is the magnetic field in the region of the rod? Assume +x is to the right, +y is up, and +z is out of the page. B = T Which of the following statements are true? The magnetic force on the bar is in the +y direction (upward). If the conventional current in the bar flowed in the opposite direction (to the left), the bar would still float at rest 6 cm above the table. If the conventional current in the bar were less than 2 A, the bar would fall.

Magnetic levitation A metal rod of length w = 11 cm and mass m = 90 grams has metal loops at both ends, which go around two metal poles (see the figure). mmass of rod W The rod is in good electrical contact with the poles but can slide freely up and down. The metal poles are connected by wires to a battery, and a current I = 2 amperes flows through the rod. A magnet supplies a large uniform magnetic field B in the region of the rod, large enough that you can neglect the magnetic fields due to the 2 ampere current. The large magnetic field is oriented to have the maximum effect. The rod floats at rest h = 6 cm above the table. What is the magnetic field in the region of the rod? Assume +x is to the right, +y is up, and +z is out of the page. B = T Which of the following statements are true? The magnetic force on the bar is in the +y direction (upward). If the conventional current in the bar flowed in the opposite direction (to the left), the bar would still float at rest 6 cm above the table. If the conventional current in the bar were less than 2 A, the bar would fall.