Which statement about the magnetic field produced by a current in a long, straight wire is correct?

Which statement about the magnetic field produced by a current in a long, straight wire is correct?

• A. The field is uniform.
• B. The field lines are directed parallel to the wire.
• C. The field lines form circles around the wire.
• D. The field increases in strength with distance from the wire.

Answer: (C)

The magnetic field produced by a current in a long, straight wire is characterized by the formation of circular field lines that encircle the wire. This behavior can be described by the right-hand rule, which states that if you grasp the wire with your right hand, with your thumb pointing in the direction of the current, your fingers will curl around the wire in the direction of the magnetic field lines. This circular pattern is a result of the magnetic field being generated by moving electric charges (the current) in the wire. The field lines are not parallel to the wire, nor are they uniform. Instead, they indicate the direction of the magnetic force that would be experienced by a hypothetical positive charge placed in the vicinity of the wire. Additionally, the strength of the magnetic field decreases with distance from the wire rather than increasing, further supporting the circular nature of the field lines around the current-carrying wire. Thus, the correct statement reflects the fundamental principles of electromagnetism, illustrating the unique and well-defined relationship between the current and the magnetic field configuration around it.

The magnetic field produced by a current in a long, straight wire is characterized by the formation of circular field lines that encircle the wire. This behavior can be described by the right-hand rule, which states that if you grasp the wire with your right hand, with your thumb pointing in the direction of the current, your fingers will curl around the wire in the direction of the magnetic field lines.

This circular pattern is a result of the magnetic field being generated by moving electric charges (the current) in the wire. The field lines are not parallel to the wire, nor are they uniform. Instead, they indicate the direction of the magnetic force that would be experienced by a hypothetical positive charge placed in the vicinity of the wire. Additionally, the strength of the magnetic field decreases with distance from the wire rather than increasing, further supporting the circular nature of the field lines around the current-carrying wire.

Thus, the correct statement reflects the fundamental principles of electromagnetism, illustrating the unique and well-defined relationship between the current and the magnetic field configuration around it.