News for hackers. Stuff that matters.

A comment on What Happens When You Drop A Magnet Inside A Copper Tube [video]. Parent comment

Re:What Happens When You Drop A Magnet Inside A Copper Tube ... by lutusp on Monday February 03, 2014 @07:25PM (#7174620)
> The inverse square law of force strength falloff ...

Because there aren't any magnetic monopoles, I believe in ordinary circumstances the relationship is inverse cube of distance. Reference: http://www.newton.dep.anl.gov/askasci/phy05/phy05629.htm

[ Parent | on HN ]
Re:What Happens When You Drop A Magnet Inside A Copper Tube ... by IgorPartola on Monday February 03, 2014 @08:01PM (#7174758)
Yup, magnetic field falls off as 1/(distance3). That's why being 5 feet from an NMR magnet is bad news bears, while being 8 feet away is fine (numbers made up, do not test). I remember seeing signs all over the place at our labs at the uni, saying to not enter if you wear a pacemaker or if you are wearing a wrist watch.
[ Parent | on HN ]