| Chronology | Current Month | Current Thread | Current Date |
| [Year List] [Month List (current year)] | [Date Index] [Thread Index] | [Thread Prev] [Thread Next] | [Date Prev] [Date Next] |
On May 2, 2017, at 8:29 PM, brian whatcott <betwys1@sbcglobal.net> wrote:
I lately took to writing responses on the Quora Q&A site for recreation. I rarely stray from electronics and one or two othersubject areas where I have some insight. But the other day, withinternal alarm bells ringing, I strayed into a basic physics question,where some high-schooler (?) transcribed a question directly from somequestion paper, as they sometimes do.
You will recognize it, I expect. Two spheres of 4 and 6 cm radius are charged to 80 and 60 uCoulomb respectively. How is the charge redistributed when the spheres are connected with a wire? I answered on general principle, in this way: the charge is redistributed in proportion to the spheres' surface area. 4^2 / (4^2 + 6^2) X (80 + 60) uC and 6^2 / (4^2 + 6^2 ) X (80 + 60) uC. about 43 : 97 uC I was surprised to find (when I finally checked) that the charge division (as given in online sources) is proportional to spheres' radii, not area. 56 : 84 uC How was I so easily falsified? Brian W
_______________________________________________
Forum for Physics Educators
Phys-l@mail.phys-l.org
http://www.phys-l.org/mailman/listinfo/phys-l