Which of the following describes the resistance of a magnet to being demagnetized by another magnetic field?

• A. Coercivity
• B. Permeability
• C. Remanence
• D. Magnetization

Answer: (A)

Coercivity is the property that tells how strong an opposing magnetic field must be to reduce a magnet’s net magnetization to zero. It describes the material’s resistance to demagnetization when faced with external fields; a high coercivity means it takes a powerful opposite field to flip the domains, so the magnet stays magnetized. Permeability, by contrast, is about how easily magnetic flux passes through a material and how easily it becomes magnetized in response to a field, not how resistant it is to losing magnetization. Remanence measures the remaining magnetization after the external field is removed, indicating how strong the magnet is still, rather than how hard it is to demagnetize. Magnetization is the process or state of the material having magnetic moments aligned, not the resistance to demagnetizing influence. Materials with high coercivity, like strong permanent magnets, resist demagnetization well, which is exactly what this term captures.