Magnetic Field Lines

Magnetic Field Lines are the imaginary lines around the source of a magnet or any other magnetic substance. Magnetic field lines help us in understanding the behavior of magnetic poles and magnetism. Magnetic fields are the imaginary lines outside a magnet that are helpful to explain the properties of a magnet. In this article, we will explain how magnetic field lines are produced when current flows through a conductor and how they exert a force on any magnetic pole located in the region. 

This article aims to provide a complete understanding of magnetic field lines and their properties. So, let’s start learning about Magnetic Field Lines and their properties.

Magnetic Field Definition

Magnetic field is the region around a magnet or a current-carrying conductor within which the force of magnetism can be observed. 

The magnetic field is a vector quantity generated by moving charges. Magnetic and electric forces are part of the four fundamental forces of nature. Electric and magnetic forces interact with each other to form electromagnetic forces, which are an essential part of modern engineering infrastructure and development.

Magnetic Field Lines

The magnetic field line is the pathway alongside which the adjacent north pole will move if it is free to do so. Since an isolated magnetic pole does not exist, a small magnetic needle is used to plot the field lines of the magnetic field. Magnetic field lines don’t exist in the physical world rather it is a concept. The concept of magnetic field lines was developed for lines to visualize the strength of the magnetic field in different regions of the field. In areas where the magnetic field lines are very close (crowded), the magnetic field is said to be very strong.

Properties of Magnetic Field Lines

Some of the properties of Magnetic Field Lines are as follows:

• Magnetic field lines are closed uninterrupted loops extending through the body of the magnet.
• The direction of the magnetic field can be determined by drawing a tangent to the magnetic field line.
• The strength of the magnetic field is directly proportional to the density or closeness of the field lines.
• The magnetic field lines originate from the north pole and terminate at the south pole.
• Within a magnet, the direction of the magnetic field lines is from the south pole to the north pole.
• Magnetic field lines do not intersect with each other.
• Magnetic field lines form closed loops.
• Magnetic field lines have both magnitude and direction at any point on the field and can be represented by a vector.
• They indicate the direction of the magnetic field.
• The magnetic field is stronger at the poles because the field lines are denser in those regions.

Magnetic Field Lines Around a Bar Magnet

The magnetic field of the bar magnet is discussed in the image below:

Magnetic Field Lines Patterns

Magnetic Field Lines make different patterns around different conductors. Some of the conductors around which magnetic field is produced are mentioned below:

• Magnetic Field Around a Bar Magnet
• Magnetic Field Around a Straight Conductor
• Magnetic Field Around a Circular Conductor 
• Magnetic Field Around a Solenoid
• Magnetic Field Around a Toroid

How to Find Direction of Magnetic Field

The direction of the magnetic field due to a current-carrying conductor can be found by applying the rules mentioned below:

• Right-Hand Thumb Rule
• Maxwell’s  Corkscrew Rule

Let’s understand these rules in detail as follows:

Right-Hand Thumb Rule 

The right-Hand Thumb Rule states that If we hold the conductor in the palm of the right hand and the thumb points in the direction of flow of current, the direction in which the fingers turn gives the direction of the magnetic field lines.

It follows that the magnetic field is in the form of concentric circles, the centers of which are located directly on the conductor.

Maxwell’s Corkscrew Rule

Maxwell’s Corkscrew Rule states that if the right-hand corkscrew is rotated so that it moves in the direction of flow through the conductor, the direction of rotation of the screw gives the edge of the magnetic field lines.

For a current flowing through a conductor in the direction shown in the diagram, both laws predict that the magnetic field lines will be in a counterclockwise direction when viewed from above.

Magnetic Field Lines Vs Electric Field Lines

The differences between magnetic field lines and electric field lines are discussed in the table below,

Magnetic Field Lines	Electric Field Lines
Produced by moving charges or magnets	Produced by stationary charges
Form closed loops around a magnet or current-carrying wire	Start from positive charges and end with negative charges
Do not originate from a magnetic monopole	Originate from a positive charge and terminate at a negative charge
Their density determines the strength of the magnetic field	Their density determines the strength of the electric field
Do not interact with electric charges directly	Interact with electric charges directly
Do not experience any net force	Experience a net force in the presence of other charges
Can penetrate through most materials	Are influenced by dielectric materials
Can be shielded using materials such as iron or mu-metal	Can be shielded using materials such as conductors
Can induce an electric field in a conductor when they change in strength or direction	Can induce a magnetic field in a conductor when they change in strength or direction

Read More,

• Magnetic Field on the Axis of a Circular Current Loop
• Magnetic Field due to Current carrying Conductor
• Earth’s Magnetic Field

FAQs on Magnetic Field Lines

Q1. What is a Magnet? 

Answer:

A magnet is an arrangement of two equal and opposite magnetic poles separated by a certain distance. The two main properties of magnets are attractive and directional.

Q2. Does a Separate Magnetic Pole Exist like a Separate Electric Charge?

Answer:

No, an isolated magnetic pole does not exist. If we split any magnetic dipole each part of it behaves like a dipole itself.

Q3: What are Magnetic Field Lines?

Answer:

Magnetic field lines are a graphical representation of the magnetic field that surrounds a magnet or a current-carrying wire. They are lines that are drawn in such a way that the tangent at any point on the line gives the direction of the magnetic field at that point.

Q4: State Four Properties of Magnetic Field Lines.

Answer:

The four basic properties of the magnetic field lines are,

• Magnetic field lines are closed uninterrupted loops extending through the body of the magnet.
• The direction of the magnetic field can be determined by drawing a tangent to the magnetic field line.
• The strength of the magnetic field is directly proportional to the density or closeness of the field lines.
• The magnetic field lines originate from the north pole and terminate at the south pole.

Q5: Are Magnetic Field Lines formed Closed Loops?

Answer:

Yes, Magnetic Field lines are closed loops. They start from the north pole and end at the south pole outside the magnet and inside the magnet they transect from south to north pole to complete the loop.

Q6: What is the Direction of Magnetic Field Lines?

Answer: 

The direction of magnetic field lines is from the north pole to the south pole outside the magnet and south to north inside the magnet.

Q7: What is relationship between Magnetic Field Lines and Magnetic Force?

Answer: 

Magnetic field lines represent the direction and magnitude of the magnetic force that would be experienced by a small magnetic compass placed at any point along the line. The closer the magnetic field lines are to each other, the stronger the magnetic force at that point.

Q8: Can Magnetic Field Lines Intersect?

Answer: 

No, magnetic field lines cannot intersect. This is because if two magnetic field lines intersect, it would mean that the magnetic field would have two different directions at the same point, which is not possible.