Magnetic fields are created by what, if not by magnetic monopoles?

Magnetic fields are created by what, if not by magnetic monopoles?

• A. Magnetic monopoles create fields
• B. Static electrical charges create fields
• C. Moving electrically charged particles create fields
• D. Gravitational forces create magnetic fields

Answer: (C)

Magnetic fields arise from moving electric charges and from changing electric fields. When charges flow, as in a wire, they create a magnetic field that loops around the path of the current. If charges are stationary, they produce an electric field but no magnetic field. Gravitational forces don’t generate magnetic fields in classical electromagnetism, and magnetic monopoles haven’t been observed—if they existed, they would produce magnetic fields in a way analogous to electric charges, but that’s not how magnetic fields arise today. So the source you’re looking for is moving electrically charged particles.

Magnetic fields arise from moving electric charges and from changing electric fields. When charges flow, as in a wire, they create a magnetic field that loops around the path of the current. If charges are stationary, they produce an electric field but no magnetic field. Gravitational forces don’t generate magnetic fields in classical electromagnetism, and magnetic monopoles haven’t been observed—if they existed, they would produce magnetic fields in a way analogous to electric charges, but that’s not how magnetic fields arise today. So the source you’re looking for is moving electrically charged particles.