Magnetic material property definition: Which term describes a material’s ability to remain magnetized (retain residual magnetism) after the external magnetizing force has been removed?

Introduction / Context:
Magnetic materials are characterized by several properties that influence transformer cores, memory devices, sensors, and permanent magnets. Knowing exactly what each term means helps in selecting materials and interpreting B-H curves.

Given Data / Assumptions:

• No specific numeric data; this is a definition question.
• The material has been magnetized and the external field is subsequently removed.

Concept / Approach:
Retentivity (also called remanence when referring to flux density) measures how well a material retains magnetization after the magnetizing force (H) is reduced to zero. Hysteresis describes the lag between B and H and the loop area related to energy loss; reluctance is the opposition to flux; induction is the process of generating magnetic effects from applied fields or currents. Only retentivity directly defines the ability to remain magnetized.

Step-by-Step Solution:

Verification / Alternative check:
Examine a B-H hysteresis loop: when H returns to zero, B remains at Br (remanent flux density), illustrating retentivity.

Why Other Options Are Wrong:

• Hysteresis: Describes the loop behavior and energy loss, not retention magnitude alone.
• Reluctance: Analogous to magnetic resistance, not retention.
• Induction: General phenomenon of field or emf generation, not magnetization retention.

Common Pitfalls:
Using “hysteresis” as a catch-all for magnetic behavior; the precise property of staying magnetized is retentivity/remanence.

Final Answer:
Retentivity