Magnetic force on a moving charge
Magnetic force depends on charge motion relative to the field.
Key knowledge
The magnetic part of the force on a point charge is F_magnetic = q(v × B). It is perpendicular to velocity, so that magnetic part alone does no work on the point charge.
Values and equations
F_magnetic = q(v × B); F_magnetic · v = 0
- F_magnetic
- Magnetic force vector N
- q
- Signed charge C
- v
- Charge velocity vector m s⁻¹
- B
- Magnetic flux density vector T
Conditions and scope
- v and B are evaluated in the same frame; q is signed.
- This expression concerns the magnetic contribution, not the total electric-plus-magnetic force or forces on magnetic dipoles.
Sources · 2
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
OpenStax 11.2, equation 11.1 and force direction; perpendicular-force work follows the dot product.
2026-10-10 · Classical point-charge magnetic force and zero v-dot-force only; field generation and radiation reaction are outside scope.
Foundational review
2026-10-10 · Fresh primary-source inspection of the complete compact record, including every statement, equation, quantity and material condition, followed by independent AI editorial review. This check does not certify all linked lessons or every passage of every cited publication.
Sources from other places
Agreement within this scope
The magnetic contribution q(v×B) is perpendicular to velocity and performs no work on a point charge.
A simultaneous electric force can change kinetic energy.
National Council of Educational Research and Training (NCERT)
- Moving Charges and Magnetism · Physics (2026–27 reprint) IndiaEnglish
4.2 Lorentz force; 4.3 magnetic motion
- Moving Charges and Magnetism · Physics (2026–27 reprint)
Entry details
Permanent link to this entry ↗- Record identity
- physics-magnetic-force
- Revision
- core.1
- Structured reference record
- Essential core · first collection · University core expansion