A bar magnet is inside a closed cubical box.Magnetic field lines pointing outward from the box produce positive flux, and those pointing inward produce negative magneticflux. (a) Is the total magnetic flux through the surface of the boxpositive, negative, or zero? (b) Choose the best explanation fromamong the following:I. There are more outward magnetic field lines because the magnet is inside the box.II. The magnet draws field lines inward toward itself, producingmore negative flux.III. The same number of magnetic field lines leave the box asenter it.

A bar magnet is inside a closed cubical box.Magnetic field lines pointing outward from the box produce positive flux, and those pointing inward produce negative magneticflux. (a) Is the total magnetic flux through the surface of the boxpositive, negative, or zero? (b) Choose the best explanation fromamong the following:I. There are more outward magnetic field lines because the magnet is inside the box.II. The magnet draws field lines inward toward itself, producingmore negative flux.III. The same number of magnetic field lines leave the box asenter it.