Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

What results when electrons are unpaired in a material?

1. Reduction in electrical resistance

2. Formation of a magnetic field

3. Increased voltage

4. Absence of a magnetic field

The correct answer is: Formation of a magnetic field

When electrons are unpaired in a material, it leads to the formation of a magnetic field. Electrons have intrinsic magnetic moments due to their spin, and when these spins are aligned, as occurs with unpaired electrons, they generate a net magnetic field. This is why materials with unpaired electrons, such as ferromagnetic materials (like iron), can exhibit strong magnetic properties. In contrast, paired electrons have their magnetic moments cancel out, leading to no net magnetic field being produced. The presence of a magnetic field due to unpaired electrons is a crucial concept in understanding magnetism and the behavior of materials in magnetic fields. This phenomenon is foundational in fields such as materials science, physics, and electrical engineering, influencing the design and application of various technologies, including magnets and magnetic storage devices.