ESA Certified Alarm Technician Practice Exam

A material with many free electrons is called a(n) ______________.

1. Insulator

2. Conductive material

3. Conductor

4. Semiconductor

The correct answer is: Conductor

A material characterized by many free electrons is identified as a conductor. Conductors are substances that allow the flow of electric current due to the presence of free or loosely bound electrons that can move easily within the material. Metals like copper and aluminum are prime examples, as they possess a high density of free electrons which facilitates conductivity. In contrast, insulators have very few free electrons, which restricts the flow of electricity. Semiconductors have properties that lie between conductors and insulators; their ability to conduct electricity can be altered by adding impurities or changing temperature. While conductive material is a broad term that may encompass both conductors and semiconductors, the more precise term in this context is 'conductor' to specifically denote a material that has abundant free electrons available for electrical conduction.