ESA Certified Alarm Technician Practice Exam

What happens to resistance if the temperature of a conductor increases?

1. It decreases

2. It remains the same

3. It increases

4. It fluctuates randomly

The correct answer is: It increases

When the temperature of a conductor increases, the resistance generally increases as well. This phenomenon occurs because, at higher temperatures, the metal atoms in the conductor vibrate more vigorously. This increased atomic movement causes more collisions between the charge carriers (usually electrons) and the atoms of the conductor, which impedes the flow of electricity and results in higher resistance. For most metallic conductors, the relationship between temperature and resistance is predictable and can be quantified using the temperature coefficient of resistance. As temperature rises, the resistance increases approximately linearly for many common materials within certain temperature ranges. Understanding this relationship is vital in practical applications, such as when designing electrical circuits where temperature variations may occur and their impact on resistance needs to be accounted for.