Question

Hard magnetic material is characterised by:

• A. Only low coercive force
• B. High coercive force and low residual magnetic induction
• C. High coercive force and high residual magnetic induction
• D. Low coercive force and high residual magnetic induction

Hint:

\textbf{Hard magnetic materials} are defined by their \textbf{high coercivity} and \textbf{high remanence}, making them suitable for permanent magnet applications.

Answer 1

The Correct Option is C

Step 1: Understanding Hard Magnetic Materials
Hard magnetic materials (also called permanent magnets) are those that: - Retain their magnetism after the removal of the external magnetic field, - Are difficult to demagnetize. Step 2: Key Characteristics
- High coercive force (H\textsubscript{c}): Resistance to demagnetization, - High residual magnetic induction (B\textsubscript{r}): Amount of magnetism left in the material after the external field is removed. These properties ensure that the material maintains strong magnetism in applications like motors, sensors, and permanent magnet generators. Step 3: Elimination of Incorrect Options
- Low coercive force: Characteristic of soft magnetic materials. - Low residual induction: Indicates weak permanent magnet capability. Conclusion: Hard magnetic materials are best characterized by high coercive force and high residual magnetic induction.