Magnetostactis Flashcards
What is Magnetostatic?
Magnetostatics is the study of magnetic fields in systems where the currents are steady (not changing with time). It is the magnetic analogue of electrostatics, where the charges are stationary.
What is the Magnetic force on a charge?
Force is a vector that is the cross product of the magnetic flux density and the velocity vector of the charge. Times the charge.
F=q (v×B)
What is Magnetic flux density ?
Is the B-field which is the measurement of how strong the magnetic field is, in the unit Tesla.
What is Lorentz force?
The Lorentz force is fundamental postulate of electromagnetics that describes the forces acting on charges.
It combines both the electric field and the magnetic field into one formula.
What are the two fundamental postulates of magnetostatics?
Magnetic field has zero divergence, because there are no monopoles in magnetic charges.
∇∙B=0
Curl of the magnetic field is the permeability in free space times the volume current density.
∇×B=μ0 J
What is vector magnetic potential and why do we use it ?
The vector magnetic potential (A) is a vector field that can be used to find the magnetic field, like the potential scalar field for electrostatic.
B=∇×A
What is Biot-Savart Law?
Is a way to find the magnetic field B from current I in situation where Ampere´s law cannot.
This is when I is in a circuit where closed path cannot be found and B has not constant magnitude.
What is Magnetic Dipole?
When having current moving in a loop, a magnetic field will be generated around the loop and going in the upper direction, this will be a new field which is the magnetic moment. This create a north and south pole the direction of the field is the north and opposite is south pole.
What is the magnetic moment?
Magnetic moment is the direction of the dipole field. It is tangential to the current vector.
The moment depends on the current in and on the surface area.
What is Magnetization?
Applying a magnetic field onto materials, will make the magnetic dipole moment in the atoms align with the field, generating torque, induced moment due to change in magnetic moment. This will also induce a surface and current densities known as magnetization current densities.
∇×M=JmV
M×an=JmS
What is magnetic field intensity?
Taken into account the external field that produces the magnetization field , the H-field or the magnetic field intensity is a field that tells about in intense the magnetic field is for a material.
What is Amperes law of circuital with the magnetic field intensity?
Curl of magnetic field intensity will give the current density of free currents.
∇×H=J
So in the integral form is.
Circulation of magnetic field intensity, around any closed path will be equal to the total free current, passing through the surface.
What is the relationship between magnetization and magnetic field intensity in materials?
M=χm H
For simple materials, linear , homogeneous ,and isotropic.
μr and χm is constant.
What is a magnetic circuits?
Circuits where there is ferromagnetic cores involves,the interests it to find the magnetic flux and magnetic field intensity in various parts of the circuit, that arise from the windings of carrying currents.
Such circuits are generators, inductors, transformers and motors.
What are the similarities of DC-Magnetic circuits and DC-Electric circuits?
When working with magnetic circuits analogies can be drawn to electric circuits.
Reluctance = Resistance
Flux = Current
Permeability = Conductivity
mmf = emf
