Deduced: cathode rays are negatively charged Paddle wheel discharge tube Jean Perrin (1895): cathode rays push wheels rays have mass and velocity must be particles negatively charged named electrons ratio of charge to mass of electron J.J. Thompson (1897): deflect electron beam using field E- yE = estimate of electron if known q/m vx Using to balance B-field E-field (since ) calculate = 1.76 x 1011 C/g q/m measured charge of electron R.A.Milikan (1909-11): 1.charge oil drop by rubbing against nozzle of atomizer 2. experiences upward force due to applied qE E-field 3. balance against gravity
Deduced: cathode rays are negatively charged Jean Perrin (1895): Paddle wheel discharge tube cathode rays push wheels rays have mass and velocity must be particles negatively charged named electrons J.J. Thompson (1897): ratio of charge to mass of electron deflect electron beam using E- field yE = estimate q/m of electron if vx known Using B-field to balance E-field (since ) calculate q/m = 1.76 x 1011 C/g R.A.Milikan (1909-11): measured charge of electron 1.charge oil drop by rubbing against nozzle of atomizer 2. experiences upward force qE due to applied E-field 3. balance against gravity
fintroduction-to-particle-physics2.docx