What term describes the opposition of a magnetic material to a magnetic field?

The term that describes the opposition of a magnetic material to a magnetic field is reluctance. In magnetic circuits, reluctance is analogous to resistance in electrical circuits; it quantifies how much a material resists the establishment of a magnetic flux. When a magnetic field is applied to a material, reluctance measures how easily the magnetic field can pass through that material. Higher reluctance indicates greater opposition to the magnetic field, while lower reluctance suggests that the material easily allows magnetic field lines to pass through.

In various applications within lineman work, understanding reluctance is essential when dealing with transformers, inductors, and other magnetic components. It helps in the design of efficient magnetic circuits that minimize energy loss due to opposition to the magnetic field.

The other terms in the question, while relevant in the study of magnetism, do not define the opposition to the magnetic field in the same way. Magnetomotive force relates to the strength of the magnetic field produced by current. Permeability measures how easily a material can become magnetized or conduct magnetic lines of force. Flux density, on the other hand, refers to the amount of magnetic field passing through a specified area. These concepts are interconnected, but reluctance is the specific term for the opposition a