Mass-to-charge ratio refers to the molecular or atomic mass number and "z" to the charge number of the ion; however, the quantity of "m"/"z" is dimensionless by definition. An ion of 100 atomic mass units ("m" = 100) carrying two charges ("z" = 2) will be observed at "m"/"z" = 50. In the 19th century, the mass-to-charge ratios of some ions were measured by electrochemical methods. In 1897, the mass-to-charge ratio of the electron was first measured by J. J. Thomson. By doing this, he showed that the electron was in fact a particle with a mass and a charge, and that
Emmy (given name) Emmy (given name) Emmy is a feminine (sometimes also masculine) given name. Orthographic variants include Emme, Emmi and Emmie. The name is in many instances a hypocoristic of either Emma (itself being in origin a hypocoristic of a number of ancient Germanic names beginning in "ermen") or (more rarely) Emily, or Emmanuel (Emmanuelle). It came to be used as a separate (rare) German name, given officially in Germany from the later 19th century. As an officially given feminine name, Emmy ranked 66th in Sweden and 89th in France as of 2010. Emmy is rarely also encountered as a surname. Notable