The magnetic field which is produced by an electric current.

The magnetic field which is produced by an electric current.

• A. Induced magnetic field
• B. External magnetic field
• C. Earth's magnetic field
• D. Magnetic dipole field

Answer: (A)

A current in a conductor creates a magnetic field in the surrounding space; this field is the one produced by the moving charges and is described as the induced magnetic field. The field lines circle the current (right-hand rule), and its existence is a direct result of the current itself, not something applied from outside. For a straight wire, the field magnitude falls off with distance as B ∝ 1/r, while for a loop the field resembles a magnetic dipole near far away, but in all cases the field is generated by the current. External magnetic fields come from sources outside the system, the Earth’s field comes from geophysical processes, and a magnetic dipole field is a specific pattern arising from certain current geometries at a distance. The field produced by the current is, by definition, the induced magnetic field.

A current in a conductor creates a magnetic field in the surrounding space; this field is the one produced by the moving charges and is described as the induced magnetic field. The field lines circle the current (right-hand rule), and its existence is a direct result of the current itself, not something applied from outside. For a straight wire, the field magnitude falls off with distance as B ∝ 1/r, while for a loop the field resembles a magnetic dipole near far away, but in all cases the field is generated by the current.

External magnetic fields come from sources outside the system, the Earth’s field comes from geophysical processes, and a magnetic dipole field is a specific pattern arising from certain current geometries at a distance. The field produced by the current is, by definition, the induced magnetic field.