[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

*To*: tesla@xxxxxxxxxx*Subject*: RE: Physics of Wireless Transmission (Units)*From*: "Tesla list" <tesla@xxxxxxxxxx>*Date*: Sun, 23 Apr 2006 17:22:56 -0600*Delivered-to*: testla@xxxxxxxxxx*Delivered-to*: tesla@xxxxxxxxxx*Old-return-path*: <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>*Resent-date*: Sun, 23 Apr 2006 17:09:49 -0600 (MDT)*Resent-from*: tesla@xxxxxxxxxx*Resent-message-id*: <3ETQT8eY3ZL.A.fUC.9kATEB@chip1>*Resent-sender*: tesla-request@xxxxxxxxxx

Original poster: "Godfrey Loudner" <ggreen@xxxxxxxx> Hello Dave The expression you refer to is I/(2 Pi epsilon c^2 R) where I is current, epsilon is the permittivity of free space, c is the of the speed of light, and R is distance. In the MKS system of units, I is Ampere, epsilon is Coulomb^2/(Newton meter^2), c is meter/sec, and R is meter. Now the dimension of (epsilon c^2 R) is (C^2/(N m^2))(m^2/s^2)m = C^2 m/(N s^2). So the dimension of the expression is A N s^2/(C^2 m) = (C/s)N s^2/(C^2 m) = s N/(C m) = N/[(C/s) m] = N/(A m)= Tesla. Tesla is the unit for the magnetic field B. So there is nothing wrong with the expression in the sense of units. BTW thanks for an article that makes really good reading. I think there's enough there to answer Gerry's question. Godfrey Loudner Hi Terry, Bob, and all, I have found a web page that presents the mathematics behind relativistic charge: http://physics.weber.edu/schroeder/mrr/MRRtalk.html You will note in equation 3 it says, "The expression in parentheses must be the magnetic field strength." When you work out the actual dimensions for the term in the parentheses, you get mass per time, which is not the unit of magnetic field strength. Dave

- Prev by Date:
**Re: Physics of Wireless Transmission** - Next by Date:
**Re: Physics of Wireless Transmission** - Previous by thread:
**Re: electromagnetic wave fundamental frequency and harmonic series?** - Next by thread:
**Re: Physics of Wireless Transmission (Units)** - Index(es):