AFOQT Practice Test

What creates a magnetic field around a charged object?

1. Electric current

2. Magnetic materials

3. Excess electrons

4. Static electricity

The correct answer is: Electric current

The creation of a magnetic field around a charged object is primarily due to the flow of electric current. When charged particles, such as electrons, move through a conductor, they generate a magnetic field in the surrounding space. This phenomenon is a fundamental principle of electromagnetism and is described by Ampère's law, which states that magnetic fields are produced by electric currents. In contrast, while magnetic materials can be influenced by magnetic fields and can become magnets themselves, they do not create a magnetic field in response to their presence alone. Excess electrons might contribute to charges on an object, but they do not by themselves create a magnetic field unless they are in motion, which constitutes an electric current. Static electricity refers to a buildup of electric charge at rest; it does not involve movement and thus does not produce a magnetic field. Overall, the key factor that generates a magnetic field is the movement of electric charges, specifically in the form of electric current.