Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1a 12/4/83; site rlgvax.UUCP Path: utzoo!watmath!clyde!floyd!harpo!seismo!rlgvax!guy From: guy@rlgvax.UUCP (Guy Harris) Newsgroups: net.physics Subject: Re: eV Revisited Message-ID: <1686@rlgvax.UUCP> Date: Wed, 8-Feb-84 22:51:42 EST Article-I.D.: rlgvax.1686 Posted: Wed Feb 8 22:51:42 1984 Date-Received: Fri, 10-Feb-84 03:34:52 EST References: <1559@pur-ee.UUCP> Organization: CCI Office Systems Group, Reston, VA Lines: 15 > Mass and energy are related to each other by a constant. This > constant is c^2. If you know something's mass and want the energy > associated with that mass, you use the well known equation E=mc^2. > Likewise, to obtain mass from energy, divide the energy by c^2. > The point of the whole thing is this. You cannot specify mass > by using units of energy. You have to use units of mass, and the > unit of mass associated with eV is eV/c^2. Not simply eV. However, given that c^2 is a constant, you can specify mass by giving the energy equivalent of that mass; saying that the electron has a mass of .511 MeV is more convenient than saying it has a mass of .511 MeV/c^2, so the e-/e+ mass is conventionally given as .511 MeV. Guy Harris {seismo,ihnp4,allegra}!rlgvax!guy