Correct AnswerA. Diamagnetic
Quick Explanation
A diamagnetic material has permeability slightly below that of free space, equivalently relative permeability μr slightly less than 1. It develops a weak magnetization opposite to the applied field.
Detailed Explanation
Concept & Reasoning
The wording compares material permeability with free-space permeability. Since μ = μ0 μr, a material with μ < μ0 has μr < 1 and is diamagnetic. Paramagnetic substances have μr slightly greater than 1, while ferromagnetic materials can have μr many times larger than 1. Diamagnetism is weak and generally associated with negative magnetic susceptibility.
How to Solve It in the Exam
μ below μ₀ ⇒ μr below 1 ⇒ diamagnetic.
Important Exam PointTranslate permeability wording into relative permeability before selecting the material class.
Related Revision Path
This question sits in the revision path Electromagnetic Fields → Magnetic Materials → Magnetic Properties .
