3. A 4.6 g wire is bent into a circular loop with a 10 cm radius. The gravitational force on the loop points in the -y-direction. The upper half of the loop passes through a 0.8 T magnetic field pointing in the -z-direction (into the page) and confined to a limited region of space. The magnitude and direction of the magnetic field are constant within the indicated region. The magnetic field is zero outside of the region. Magnetic field region X X X X X X B X X X 10 cm x grav X X XX A current flows in the loop, but the direction and magnitude of the current are unknown. (a) If the loop is levitating (i.e., experiencing zero net force), what direction (clockwise or counterclockwise) must the current be flowing in? Explain. (b) Find the magnitude of the current such that the loop levitates.

3. A 4.6 g wire is bent into a circular loop with a 10 cm radius. The gravitational force on the loop points in the -y-direction. The upper half of the loop passes through a 0.8 T magnetic field pointing in the -z-direction (into the page) and confined to a limited region of space. The magnitude and direction of the magnetic field are constant within the indicated region. The magnetic field is zero outside of the region. Magnetic field region X X X X X X B X X X 10 cm x grav X X XX A current flows in the loop, but the direction and magnitude of the current are unknown. (a) If the loop is levitating (i.e., experiencing zero net force), what direction (clockwise or counterclockwise) must the current be flowing in? Explain. (b) Find the magnitude of the current such that the loop levitates.