A program attended by Dijia traditional cakes

If n magnetic monopoles pass through the superconducting coil, when the magnetic monopoles approach the coil, the magnetic flux passing through the coil increases, and the direction of the magnetic field is from top to bottom. Therefore, according to Lenz's law, the direction of induced magnetic field: from top to bottom, the direction of induced current can be determined counterclockwise by the right-hand spiral law; When the magnetic monopole is far away from the coil, the magnetic flux passing through the coil decreases, and the direction of the magnetic field is from bottom to top. Therefore, according to Lenz's law, the direction of the induced magnetic field is from bottom to top, and then the direction of the induced current can be determined to be counterclockwise by the right-hand spiral law. Therefore, the direction of the induced current generated in the coil remains unchanged. So, A is wrong and B is right.

Because there is no resistance in the superconducting coil, the induced current will last for a long time, and the induced electromotive force is not constant, so C is wrong and D is right.

So choose: BD.