Magnetic force is a function of position?

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Discussion Overview

The discussion revolves around whether magnetic forces can be represented as functions of position alone, or if they also depend on other factors such as velocity and time. Participants explore the relationship between magnetic forces and their dependence on various parameters, including the implications of classical and quantum mechanics.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant questions if magnetic forces can depend solely on position (x, y, z) without involving higher derivatives or other factors.
  • Another participant references the Biot-Savart Law as relevant to the discussion of magnetic fields and forces.
  • It is noted that the magnetic field from currents depends on position and can also vary with time if the currents change.
  • A participant explains that the magnetic force on a charged particle, described by the Lorentz force equation, depends on the velocity of the particle and the magnetic field, which in turn depend on spatial coordinates and time.

Areas of Agreement / Disagreement

Participants express differing views on the dependence of magnetic forces on position versus other factors like velocity and time. There is no consensus reached on the question posed.

Contextual Notes

The discussion includes references to classical physics concepts (Lorentz force) and quantum mechanics, indicating a potential overlap in understanding that may not be fully resolved. The implications of time-varying currents on magnetic fields are also noted but not fully explored.

neelakash
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Sir,can you tell me if magnetic forces are function of
position?Possibly,I read it somewhere in internet forums that magnetic
forces are functions of velocity.I have read in your QM book's first
page that---in microscopic level all type of force may be written as
-∂V/∂x...except magnetic forces.
Normally,forces are functions of position,velocity and time...I want
to know if the magnetic forces can be represented as function of
position only.I mean can we have a magnetic force depending on only
(x,y,z) and NOT their higher derivatives as well?
Please let me know.Your help will be greatly appreciated
 
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Please refer to the Biot-Savart Law.

In addition, please do not start your post with "Sir". We have many women on this forum who are either physicists, or interested in physics, who could have answered your question.

Zz.
 
The magnetic field produced by a configuration of currents depends on position. It also depends on time if the currents vary with time.

The magnetic force that this field produces on a moving charge or current element therefore depends on position and time as described above, and on the velocity (b0th magnitude and direction) of the moving charge, or magnitude and direction of the current element.
 
neelakash said:
Sir,can you tell me if magnetic forces are function of
position?Possibly,I read it somewhere in internet forums that magnetic
forces are functions of velocity.I have read in your QM book's first
page that---in microscopic level all type of force may be written as
-∂V/∂x...except magnetic forces.
That's strange, you are asking about classical physics (ie the Lorentz force) yet you have been reading in a QM book ?

Your answer is this : the force exerted by a mangetic field B on a charged (q) particle is called the Lorentz force F = qv x B. The x means vector product ! Both velocity v (of the charged particle) and B depend on coordinates t (time), x,y and z, by definition. The force F therefore indeed depends on spatial coordinates and time t.

marlon
 
Last edited:

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