Magnetic Field Due to a Current Carving Cylindrical Coil (or Solenoid)

A solenoid is a coil of wire, typically wound in a helical shape, designed to generate a magnetic field when an electric current passes through it. This magnetic field closely resembles that of a bar magnet, exhibiting distinct north and south poles.

Characteristics of the Magnetic Field in a Solenoid:

• Within the solenoid, the magnetic field lines are parallel and evenly spaced, indicating a uniform magnetic field. This uniformity means the magnetic field strength is consistent at all points inside the solenoid.
• The solenoid's magnetic field pattern is similar to that of a bar magnet, with field lines emerging from one end (north pole) and entering the other end (south pole). This similarity allows solenoids to function as electromagnets in various applications.

Pattern of the magnetic field produced by Solenoid and Bar Magnet

The direction of the magnetic field and the identification of the north and south poles can be determined using the right-hand rule:

• Curl the fingers of your right hand in the direction of the current flow through the coils.
• Your thumb, pointing along the axis of the solenoid, indicates the direction of the magnetic field inside the solenoid, pointing from the south pole to the north pole.

The strength of the magnetic field inside a solenoid depends on:

• Number of Turns per Unit Length (n): More turns per unit length result in a stronger magnetic field.
• Current (I): Increasing the current passing through the solenoid enhances the magnetic field strength.
• Core Material: Inserting a material with high magnetic permeability, such as iron, into the solenoid increases the magnetic field strength.