Magnetic Field Line

Magnetic field lines are imaginary lines used to represent magnetic field, and a tangent to it depicts the direction of the magnetic force. The moving charges and magnets produce the magnetic field lines. Some important properties of magnetic field lines are as follows,

• Two magnetic field lines never intersect each other.
• Magnetic field lines are continuous closed loops.
• They are directed from the north pole to the south pole of the magnet (outside the magnet) and directed from the south pole to the north pole of the magnet (inside the magnet).
• The tangent at any point on the magnetic field lines gives the direction of the magnetic force at that point.
• The closer the magnetic field lines, the stronger will be the magnetic force and vice-versa.
• Magnetic field lines are crowded near the poles and less dense when away from the poles.

The image of Magnetic Field Lines by a bar magnet is shown in the image below,

Example: Find the magnitude of the magnetic field that is 0.10 m away from a wire carrying a 3.00 A current. Also, if the current has a vector direction out of the page (or screen), then what is the direction of the magnetic field?

Given,

• r = 0.10 m
• I = 3.00 A

By using the formula we can calculate the magnetic field,

B = μ₀I/2πr

Substituting the values, 

B = (4π × 10⁻⁷ T⋅m/A)(3.00 A)2π(0.10 m)

B = (4π × 10⁻⁷ T⋅m/A)(3.00 A)2π(0.10 m)

B = (4π × 10⁻⁷)(3.00)2π(0.10) T

B = (4π × 10⁻⁷)(3.00)2π(0.10) T

B = 4π(3.00)2π(0.10) × 10⁻⁷ T

B = 2(30.0) × 10⁻⁷ T

B = 60.0 × 10⁻⁷ T

B = 6.0 ×10⁻⁶ T [Since 10^-6 T = 1 μT]

B = 6.0 μT

Difference between an Electric Field and a Magnetic Field is Electric Field is the region around an electric charge in which another charge experiences the force of attraction and repulsion, whereas a magnetic field is the region around magnetic material in which it attracts or repels other magnetic materials.

Before learning the difference between an electric field and a magnetic field, let’s learn about what is electric field and what is magnetic field, their difference, and others in detail.