Question

Materials suitable for permanent magnets should have:

• A. Low retentivity and low coercivity
• B. Low retentivity and high coercivity
• C. High retentivity and low coercivity
• D. High retentivity and high coercivity

Hint:

Materials used for permanent magnets should have high retentivity to maintain magnetization and high coercivity to resist demagnetization.

Answer 1

The Correct Option is D

Step 1: Understanding Retentivity and Coercivity - Retentivity refers to the ability of a material to retain magnetization after the external magnetic field is removed. - Coercivity refers to the ability to withstand demagnetization by an external force. Step 2: Characteristics of Permanent Magnets Permanent magnets require: - High retentivity to ensure they retain magnetization for a long time. - High coercivity to resist external influences that could demagnetize them. Thus, materials suitable for permanent magnets must possess both high retentivity and high coercivity. Conclusion Thus, the correct answer is: \[ \text{High retentivity and high coercivity} \]