What fault causes resistance to increase or decrease?

The correct answer is based on the concept that when there is a change in the electrical system, such as components wearing out, connections becoming loose, or materials degrading, the resistance in a circuit can either increase or decrease. This phenomenon of resistance changing with a change in a circuit element is commonly referred to as a "changed value."

When electrical components, such as resistors or connectors, undergo conditions like age, heat, or mechanical stress, their electrical characteristics—including resistance—can vary significantly. An increase in resistance can lead to less current flowing through, while a decrease in resistance allows more current to flow, which can drastically affect the functionality of the circuit. Understanding this principle is crucial for diagnosing issues in electrical systems where performance is impacted by component condition.

In contrast, the other options presented do not pertain directly to the nature of resistance change due to fault. A short circuit typically implies a direct connection that bypasses the intended path, often leading to a drop in resistance but not a change in value in the traditional sense. Surge protectors are designed to safeguard against voltage spikes, but they do not directly change resistance in a circuit. Finally, power fluctuations refer to variations in voltage and current supply, rather than direct effects on the resistance of