NEIEP Mechanics Practice Exam

An example of a reactive component that can store energy for long periods of time, causing electrical hazard even with the power removed is?

1. Inductor

2. Resistor

3. Capacitor

4. Transistor

The correct answer is: Capacitor

A capacitor is a reactive component designed to store electrical energy in the form of an electric field. When charged, capacitors can hold this energy for extended periods, which can pose an electrical hazard even after the power is turned off. This is particularly significant because, unlike resistors, which dissipate electrical energy as heat, capacitors can maintain a charge that may be released unexpectedly. In practical scenarios, capacitors, especially large ones used in power electronics or in motor starting applications, can maintain a significant voltage long after the power source has been disconnected. This retained voltage can potentially cause electric shock if a person inadvertently makes contact with the charged terminals. Other options, like inductors, do store energy but usually discharge quickly when the power is removed; resistors do not store energy at all and instead convert it into heat; while transistors are active components that control electrical signals but do not store energy in the same way capacitors do. Thus, the characteristics of a capacitor specifically align with the question's requirements for a reactive component that poses lasting electrical hazards.