Wednesday, October 14, 2015

The magnetic field B is defined from the Lorentz Force Law, and specifically from the magnetic force on a moving charge: The force is perpendicular to both the velocity v of the charge q and the magnetic field B.

Magnetic Force

The magnetic field B is defined from the Lorentz Force Law, and specifically from the magnetic force on a moving charge:
The implications of this expression include:
1. The force is perpendicular to both the velocity v of the charge q and the magnetic field B.
2. The magnitude of the force is F = qvB sinθ where θ is the angle < 180 degrees between the velocity and the magnetic field. This implies that the magnetic force on a stationary charge or a charge moving parallel to the magnetic field is zero.
3. The direction of the force is given by the right hand rule. The force relationship above is in the form of a vector product.
When the magnetic force relationship is applied to a current-carrying wire, the right-hand rule may be used to determine the direction of force on the wire.
From the force relationship above it can be deduced that the units of magnetic field are Newton seconds /(Coulomb meter) or Newtons per Ampere meter. This unit is named the Tesla. It is a large unit, and the smaller unit Gauss is used for small fields like the Earth's magnetic field. A Tesla is 10,000 Gauss. The Earth's magnetic field at the surface is on the order of half a Gauss.
Magnetic interactions with chargeMagnetic force applications
Index

Electromagnetic force

Magnetic field concepts

HyperPhysics***** Electricity and Magnetism R Nave
Go Back






Lorentz Force Law

Both the electric field and magnetic field can be defined from the Lorentz force law:
The electric force is straightforward, being in the direction of the electric field if the charge q is positive, but the direction of the magnetic part of the force is given by the right hand rule.
Index

Electromagnetic force

Magnetic force

Magnetic field concepts

HyperPhysics***** Electricity and Magnetism R Nave
Go Back






Right Hand Rule

The right hand rule is a useful mnemonic for visualizing the direction of a magnetic force as given by the Lorentz force law. The diagrams above are two of the forms used to visualize the force on a moving positive charge. The force is in the opposite direction for a negative charge moving in the direction shown. One fact to keep in mind is that the magnetic force is perpendicular to both the magnetic field and the charge velocity, but that leaves two possibilities. The right hand rule just helps you pin down which of the two directions applies.
For applications to current-carrying wires, the conventional electric current direction can be substituted for the charge velocity v in the above digram.
Magnetic force as a vector product
Magnetic force on a moving charge
Index

Magnetic force

Magnetic field concepts

HyperPhysics***** Electricity and Magnetism




[PDF]Download as a PDF - CiteSeer
citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.172.7512...
by NH MEYERS - ‎Cited by 5 - ‎Related articles
the Lorentz force in vacuum. The quantity d(qd)/dt is the apparent polarization current seen by the laboratory observer. Therefore, the dot product of these two ...

Classical Electricity and Magnetism: Second Edition

https://books.google.com/books?isbn=0486132250
Wolfgang K. H. Panofsky, ‎Melba Phillips - 2012 - ‎Science
... magnetic field by choosing a suitable Lorentz frame, whereupon the solution may be much simplified. 18-3 The Lorentz force in vacuum. The Lorentz force per ...

[PDF]its_motoasca_20031006.pdf (1.6 MB) - TU Delft Institutional ...

repository.tudelft.nl/assets/uuid...2dd9.../its_motoasca_20031006.pdf
by TE Motoasca - ‎2003 - ‎Cited by 11 - ‎Related articles
Oct 6, 2003 - This approach starts with the expression for the Lorentz force in vacuum and the assumption of an underlying microscopic model for matter, e.g. ...

[PDF]Classical Electricity and Magnetism 2nd. Ed..pdf - Fisica.net

www.fisica.net/.../PANOFSKY%20AND%20PHILIPS%20-%20Classical...
... FORMULATION 0F ELECTRODYNAMICs. 18—1. 18—2. 18—3. The four-vector potential . The electromagnetic field tensor . The Lorentz force in vacuum. 229.

Textbook Contents

www.physics.buffalo.edu/phy514/tocs.html
The Lorentz force in vacuum § 4. Covariant description of sources in material media § 5. The field equations in a material medium § 6. Transformation properties ...

Direct PhD | Indian Institute of Technology Ropar

www.iitrpr.ac.in/hi/.../directphd
Indian Institute of Technology Ropar
Loading...
... Relativistic electrodynamics: electromagnetic field tensor, Lorentz force in vacuum, energy-momentum tensor in material media, radiation reaction; mechanical ...

[PDF]CLASSICAL ELECTRICITY MAGNETISM - GBV

www.gbv.de/dms/ilmenau/toc/020234783.PDF
... OF ELECTRODYNAMICS . . . 324. 18-1 The four-vector potential. 324. 18-2 The electromagnetic field tensor. 327. 18-3 The Lorentz force in vacuum. 331 ...

No comments:

Post a Comment