Charged particle in a magnetic field

Helicoidal motion of a charged particle in a uniform magnetic field. For other animations like this one, please visit http://web.ncf.ca/ch865

Category:

Education

Tags:

• physics
• electricity
• magnetism
• animation
• pov-ray
• helicoidal
• motion
• science

[evhgl87]

magnetic field vectors point in the opposite direction of expected current flow with the magnitude of the vectors shown here as elongated lines (the arrows should be at the end to show a vector though, not centered). it is a proton particle, therefore the motion in the video is indeed correct. thanks for sharing.

[PelletierPhysics]

@evhgl87 The arrows are centered because these are magnetic field lines, not magnetic field vectors. The magnitude of the magnetic field is proportional to the density of the lines instead of being proportional to their length.

[evhgl87]

@PelletierPhysics interesting they do not teach this in upper level introductory physics? learn something new every day. is the density an indication of relative thickness or simply a viewing of transparency?

[PelletierPhysics]

@evhgl87 Magnetic field lines are used in all my electromagnetism textbooks. The magnetic field is stronger where the lines are closer to each other, and weaker where there is a larger distance between the lines. What textbook did you use?

[PelletierPhysics]

@nero314100 What you describe would be correct for a magnetic field caused by the motion of the charged particle. Here the particle is not the cause of the magnetic field. The magnetic field produces a magnetic force directed toward the center (centripetal force).

[seljer]

F = e * (v x B)

with v and B being vectors, and the cross product giving a vector perpendicular to both v and B

and since its always perpendicular to the velocity, its working as a centripental force = circular path

clockwise...because of that entire right-hand rule thing (v is before B)

if the charge were opposite then it'd be spilling in the other direction

[SharinganFY]

in which direction is the initial velocity of the particle??

[mechanicalbu11]

i do not understand why the point charge is revolving, should it be moving to the left linearly or perpendicularly to the field? what force is making the point charge behave in a radius motion?

[evhgl87]

@PelletierPhysics I looked into my textbook from previous semesters and they are indeed briefly indexed, but never instructed. The professor was a PHD graduate from Brazil but knew very little about electronics, possible that this mixed with a language barrier could be to blame. Thanks again for sharing.

[FlubsyMalone]

@PelletierPhysics it would go in the other direction if it was a negatively charged particle... so the video's correct

[PelletierPhysics]

@YamiPoyo You hypothesis is interesting, but there's a centripetal force in every circular motion, even when the particle in circular motion has an electric charge...

[YamiPoyo]

@PelletierPhysics centripetal force has nothing to do with electro dynamics.