ESA Certified Alarm Technician Practice Exam

What is produced when an alternating current flows through a coil of wire?

1. Capacitance

2. Magnetic field

3. Static electricity

4. Electrolysis

The correct answer is: Magnetic field

When an alternating current (AC) flows through a coil of wire, it generates a magnetic field around the coil due to the flow of electric charge. This is a fundamental principle of electromagnetism, specifically described by Faraday's law of electromagnetic induction. The direction and magnitude of this magnetic field change as the alternating current varies, creating a dynamic magnetic field. This property is utilized in many applications, such as transformers, inductors, and electric motors, where the interaction between magnetic fields and electric currents is essential for operation. The ability of a coil carrying AC to produce a magnetic field is key to the functioning of various electrical devices and systems, making it a crucial concept in electrical engineering and alarm technology. On the other hand, capacitance relates to the storage of electric charge in capacitors and does not directly result from current flow through a coil. Static electricity refers to electric charges at rest, which does not apply to the flowing current in this scenario. Electrolysis involves the chemical decomposition of a substance due to an electric current passing through a solution, which is also not relevant when discussing the interaction of AC with a coil of wire. Thus, the generation of a magnetic field is the direct and correct outcome of alternating current passing through a coil