What is the term for a measure of a substance's ability to conduct magnetic lines of force?

Permeability is the term that specifically refers to a substance's ability to conduct magnetic lines of force. In the context of magnetism, permeability quantifies how easily a magnetic field can penetrate and pass through a material. This property is crucial in understanding how materials interact with magnetic fields, such as in transformers, inductors, and other electrical equipment. High permeability indicates that a material allows magnetic lines to pass through easily, while low permeability suggests that it is more resistant to magnetic field penetration. This makes permeability a key factor in designing electrical components that rely on magnetic fields.