What is Magnetic force: Definition and 413 Discussions

In physics (specifically in electromagnetism) the Lorentz force (or electromagnetic force) is the combination of electric and magnetic force on a point charge due to electromagnetic fields. A particle of charge q moving with a velocity v in an electric field E and a magnetic field B experiences a force of





F

=
q


E

+
q


v

×

B



{\displaystyle \mathbf {F} =q\,\mathbf {E} +q\,\mathbf {v} \times \mathbf {B} }
(in SI units). It says that the electromagnetic force on a charge q is a combination of a force in the direction of the electric field E proportional to the magnitude of the field and the quantity of charge, and a force at right angles to the magnetic field B and the velocity v of the charge, proportional to the magnitude of the field, the charge, and the velocity. Variations on this basic formula describe the magnetic force on a current-carrying wire (sometimes called Laplace force), the electromotive force in a wire loop moving through a magnetic field (an aspect of Faraday's law of induction), and the force on a moving charged particle.
Historians suggest that the law is implicit in a paper by James Clerk Maxwell, published in 1865. Hendrik Lorentz arrived at a complete derivation in 1895, identifying the contribution of the electric force a few years after Oliver Heaviside correctly identified the contribution of the magnetic force.

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  1. S

    Can a constant magnetic field cause circular motion?

    So, I have an apparent paradox: Consider a particle moving with constant velocity, v, along the x-axis. It now enters a constant magnetic field with is parallel to the y-axis. So there is a force, F=q(vxB) which acts on it, and points in the positive z-direction at first, but then as the...
  2. N

    Direction of the magnetic force

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  3. G

    Relativistic explanation for magnetic force between perpendicular wires

    I have read about how magnetism arises from electric interactions and relativity. But in that respect i don't see how perpendicular wires can exert magnetic forces on each other. The movement of the charges is perpendicular so length contraction does not occurr in the direction of the current...
  4. J

    Central Magnetic Force between Earth and Moon

    Hey guys I have a question about central magnetic forces between the Earth-Moon system and how they would work at a very large scale similar to that of the central gravitational force. I don't know about electromagnetism as well as I do basic celestial mechanics, so I'm at a loss as to how I...
  5. U

    Is Principle of Relativity compatible with Magnetic force

    Hello friends, A while back I raised the similar question regarding absolute nature of Magnetic force due to a current carrying wire on a moving charge. But supposedly I was shown to be incorrect. Since, Magnetic filed is a relativistic effect, then every magnetic force should be...
  6. J

    Magnetic force on one electron

    Homework Statement question - see image Homework Equations The Attempt at a Solution so I use the equation F = BIl F = 0.2 * 0.4 * 8 = 0.64 Surely I just divide it by the number of electrons (8*1028) to get the answer BUT this does not give the correct answer. The correct answer is D?
  7. B

    Magnetic force in a moving inertial reference frame

    A charged particle is placed next to a current-carrying wire. The wire produces a magnetic field, but if the particle is at rest, the field exerts no force on it. However, in a different inertial reference frame moving at speed v parallel to the wire, the particle is seen to be in motion, and so...
  8. D

    What Is The Relationship Between Temperature and Magnetic Force?

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  9. N

    Charges moving parallel to magnetic fields and direction of magnetic force

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  10. L

    Magnetic Force on Various Sides of Spinning Loop?

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  11. T

    Physics Question about Magnetic Force & parallel wires

    I have a homework question that I am having some trouble with. This is my first post - so be easy on me. Question: A weight-lifter is able to hold a barbell with a maximum total mass of 205 kg above his head. A physicist uses him to conduct a classroom demonstration, asking him to hold one...
  12. T

    Magnetic force of one, moving charged particle on another (vector problem)

    Homework Statement At a particular instant, charge q_1 = 4.80×10^−6 C is at the point (0, 0.250m , 0) and has velocity v_1=(9.2*10^5 m/s) i_hat. Charge q_2 = −2.50×10^−6 C is at the point (0.150m , 0, 0) and has velocity v_2 = (-5.3x10^5 m/s) j_hat. At this instant, what is the magnetic...
  13. M

    In which situation is the magnetic force nonzero?

    Homework Statement A particle moves through a magnetic field. In which situation is the magnetic force nonzero? A. The charge is zero and the particle is moving perpendicular to the magnetic field. B. The charge is negative and the particle is moving in the direction of the magnetic field...
  14. D

    Magnetic Force Inverse Cubed Law?

    I was reading <crackpot link removed> and was wondering if the inverse cube law for magnetic force still applied for situations where the object being attracted isn't another magnet itself? E.g. if there is an electromagnet attracting an iron nut is the rule still inverse cube and not inverse...
  15. C

    Magnetic Force in a Current Carrying Wire

    Homework Statement The current in a wire consists of n electrons per unit volume moving with a velocity v. What is the effect on these electrons of the magnetic field set up by the current itself within the wire? What is the force on one electron at a distance r from the centre of the wire...
  16. A

    Magnetic Force Experienced by a Loop of Wire

    Homework Statement The problem is shown in the link below: http://postimage.org/image/do2b7xz0b/ Homework Equations Biot-Savart Law's and dF=Idl x B The Attempt at a Solution My attempt is really just a mess. I essentially want to break it up into 2 segments. (1) Being the...
  17. J

    Computing for magnetic force. Please check my answer.

    Homework Statement Find the magnitude and direction of the magnetic force on a charged particle with charge -4nC and velocity \vec{v} = (2.5\times 10^{4}) \hat{i} + (1.1 \times 10^{4}) \hat{j} (m/s) if the magnetic field in the region is given by \vec{B} = (1.2\times...
  18. E

    Amount of a magnetic force to alter the trajectory of a photon

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  19. N

    Magnetic Force Direction Question

    Homework Statement r= 0.12m B = 0.0720T I = 21.0A Fm= 0.104 N [up] A magnetic force of 0.104 N [up] acts on a 12.0cm long wire that runs[N 10 degrees E] through a magnetic field of 0.0720 T. If the current in the wire is 21.0 A, then what is the direction of the magnetic field? This...
  20. A

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  21. F

    Magnetic force does no work. OR does it?

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  22. J

    Rod of current wire exerting magnetic force on current carrying bar

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  23. G

    How Does a Magnetic Field Affect Liquid Levels in a U-Tube?

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  24. P

    Magnitude of Magnetic force on Wire

    An isolated segment of wire of length L=4.50 m carries a current of magnitude i=35.0 A at an angle theta=50.3 degrees with respect to a constant magnetic field with magnitude B= 6.70E-2 T. What is the magnitude of the magnetic force on the wire? a) 2.66 N b) 3.86 c) 5.60 N d) 8.12 N e) 11.8...
  25. B

    Why does magnetic force tend to increase magnetic energy?

    Hello. So: Why does magnetic force tend to increase magnetic energy? 1) Usually, forces go in the direction of energy minimums. Why in this case is the opposite? 2) What does it imply? What is that makes magnetism particular in some senses, for example this, for example its force function...
  26. P

    Magnetic force on a current carrying wire

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  27. F

    Is the magnetic force always 0?

    Homework Statement For any loop that may have symmetry, the magnetic force in the center must always be 0? Ex. circles, rectangles?
  28. T

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    Hi, I have some very basic question that I've been struggling to find the answer to and before I go and buy some magnets to do some test of my own I thought I'd ask here: Do two magnets of different strength repulse each other at the same strength, or does one repulse the other more...
  29. R

    Magnetic force on a charged particle

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  30. S

    Would this wheel spin from magnetic force?

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  31. E

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  32. I

    Magnetic force on rotating spherical shell

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  33. S

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  34. M

    Magnetic Force Exerted on Particle

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  35. V

    Calculating Magnetic Force on a Steel Object in a Solenoid

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  36. B

    Show that the total magnetic force on the loop is zero

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  37. C

    Magnetic force of two parallel wires is inverse proportional to distance?

    according too: http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/wirfor.html#c1F=(u * I *I2)/(2pi *r ) i thought it would be inverse proportional to the square of the distance?! can this be right?
  38. C

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  39. W

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  40. T

    Magnetic Force on a Current Carrying Wire

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  41. D

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  42. F

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  43. J

    Right hand rule finding direction of magnetic force

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  44. F

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  45. C

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  46. A

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  47. jegues

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  48. L

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  49. M

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  50. T

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