Differences between Electric Field and Magnetic Field
Contents
Comparison Article
An electric field surrounds an electrically charged particle, while a magnetic field is a region of magnetic influence, typically around a magnet or a moving electric charge.[1][2][3] Electric and magnetic fields are two aspects of the same phenomenon, known as the electromagnetic field.[4] A changing electric field can create a magnetic field, and a changing magnetic field can create an electric field.[4][5] This relationship is described by Maxwell's equations, which are a set of fundamental equations that form the basis of classical electromagnetism.
Comparison Table
| Category | Electric Field | Magnetic Field |
|---|---|---|
| Source | Stationary and moving electric charges, and time-varying magnetic fields.[1] | Moving electric charges (currents) and magnetic materials (permanent magnets). |
| Effect on Charges | Exerts a force on a charged particle, regardless of its motion.[5] | Exerts a force on a moving charged particle, perpendicular to its velocity and the field. |
| Field Lines | Originate on positive charges and terminate on negative charges; they do not form closed loops.[1] | Form continuous, closed loops, without a beginning or end. |
| Poles/Charges | Associated with positive and negative electric charges.[3] | Associated with north and south poles; magnetic monopoles have not been observed in nature. |
| Work Done | Can do work on a charged particle by changing its kinetic energy. | Does no work on a charged particle as the force is always perpendicular to the direction of motion. |
| SI Units | Newton per coulomb (N/C) or volt per meter (V/m).[2] | Tesla (T) or gauss (G).[2] |
Nature of the Fields
Electric fields are produced by electric charges.[1] The strength of an electric field depends on the magnitude of the charge creating it. The direction of the electric field is defined as the direction of the force that would be exerted on a positive test charge. Consequently, electric field lines radiate outwards from positive charges and inwards toward negative charges.[3]
Magnetic fields are generated by the movement of electric charges, such as an electric current in a wire, or by magnetic materials. The magnetic field lines of a magnet are directed from the north pole to the south pole. Unlike electric field lines, magnetic field lines always form closed loops.
Interaction with Charged Particles
A key difference between the two fields lies in their interaction with charged particles. An electric field exerts a force on any charged particle within it, whether it is stationary or moving. In contrast, a magnetic field only exerts a force on a charged particle when it is in motion.[5] This magnetic force is always perpendicular to both the velocity of the particle and the direction of the magnetic field itself. Because the magnetic force is perpendicular to the particle's motion, it changes the direction of the particle's velocity but does not change its speed or kinetic energy; therefore, a magnetic field does no work on a free charge. An electric field, however, can perform work on a charge, altering its kinetic energy.
Relationship and Electromagnetism
Electric and magnetic fields are intrinsically linked. A changing magnetic field induces an electric field, a principle known as Faraday's law of induction, which is the basis for electric generators.[4] Conversely, a changing electric field generates a magnetic field.[4] This interplay is fundamental to the propagation of electromagnetic waves, such as light, where oscillating electric and magnetic fields are perpendicular to each other and to the direction of wave travel. The complete relationship between electric and magnetic fields, charges, and currents is encapsulated in Maxwell's equations.
References
- ↑ 1.0 1.1 1.2 1.3 "wikipedia.org". Retrieved November 30, 2025.
- ↑ 2.0 2.1 2.2 "byjus.com". Retrieved November 30, 2025.
- ↑ 3.0 3.1 3.2 "thoughtco.com". Retrieved November 30, 2025.
- ↑ 4.0 4.1 4.2 4.3 "wikipedia.org". Retrieved November 30, 2025.
- ↑ 5.0 5.1 5.2 "northwestern.edu". Retrieved November 30, 2025.
