NEIEP Mechanics Practice Exam

Which of the following would describe a material that has low permeability?

1. It easily allows magnetic lines of force

2. It resists the flow of magnetic lines of force

3. It has high electric conductivity

4. It has a low melting point

The correct answer is: It resists the flow of magnetic lines of force

A material with low permeability is one that resists the flow of magnetic lines of force. Permeability is a measure of how easily a magnetic field can penetrate a material. Therefore, materials that have low permeability tend to be non-magnetic or weakly magnetic, meaning they do not allow magnetic lines of force to pass through them easily. This characteristic is important in applications like electrical and magnetic shielding, where it's essential to prevent magnetic fields from interfering with sensitive electronic components. The other options relate to different properties that do not accurately define permeability. The ability to allow magnetic lines of force to pass through easily would correspond to high permeability, not low. High electric conductivity pertains to how well a material can conduct electricity, which is not directly related to its magnetic permeability—conductivity is more about the movement of electric charges than magnetic fields. The melting point has to do with the thermal properties of a material, which is also unrelated to its magnetic characteristics. Thus, the choice that describes a low permeability material is that it resists the flow of magnetic lines of force.