After Maxwell proposed the differential equation model of the electromagnetic field in 1873, the mechanism of action of fields came into question, for
Electromagnetic Field Equation. Coulomb's Law for the electric field holds exactly only for static charges.
The unit of magnetic field strength is the Tesla (T). Comparing eq.(30.1) and eq.(30.4) we can determine the magnetic field generated by a point charge q2 moving with a velocity v2
The circular magnetic field results from moving electric charges.
The equations determine how fields arise from distributed charge and current and specify how field components are related to each other.
• In addition, magnetic fields create a force only on moving charges.
All moving charges produce a magnetic field. The magnetic field of a moving charge is very complicated but is well known. (See Jefimenko's equations.) It forms closed loops around a line that is pointing in the direction the charge is moving.
This is the equation for the magnetic force acting on a moving charged particle in a magnetic field. The angle q is the angle between the field B and the velocity v, q represents the charge of the particle.
Consider a particle of mass and electric charge moving in the uniform electric and magnetic fields, and .
This is the case portrayed in Figure 2 where a stationary conducting loop is in a time varying magnetic B field. Equation (1.3) becomes.