Which type of magnetism describes magnetism that persists without an external magnetic field?

• A. Induced magnetism
• B. Residual magnetism
• C. Permanent magnetism
• D. Dynamic magnetism

Answer: (C)

Magnetism that remains without any external field is permanent magnetism. This occurs in permanent magnets, where the internal magnetic domains stay aligned even after the external field is removed, so a noticeable magnetic effect persists. In most materials, magnetization appears only when a field is present (induced magnetism) and fades once the field is gone. Some materials can retain a leftover magnetization after the field is removed (residual or remanent magnetism), but the defining idea of permanent magnetism is that the magnetization persists in the absence of any external influence due to the material’s high coercivity and magnetic anisotropy.