Charge to Mass Ratio of Electrons electric force coils producing screen to indicate adjustable where electrons magnetic field struck electrons high voltage plates producing adjustable electric source + field magnetic force Thomson:determined the charge-to-mass ratio of electrons by balancing the force laws:Fmag-qvxB Felec-E 16
Thomson: determined the charge-to-mass ratio of electrons by balancing the force laws: Charge to Mass Ratio of Electrons - + coils producing adjustable magnetic field screen to indicate where electrons struck electric force magnetic force plates producing adjustable electric field electrons high voltage source " " " F mag = q " v × B , F elec = q " E I-16
What Thomson Found (1897) Found charge/mass ratio for electron:~1.2 x 1011 C/kg e/m for electron 1.2 x 1011 C/kg,e/m for proton =108 C/kg. Since 1.2 x 1011 C/kg >>108 C/kg,either the electron has a far greater charge than the proton,or it has far less mass. 1-17
What Thomson Found (1897) • Found charge/mass ratio for electron: ~ 1.2 × 1011 C/kg • Since 1.2 × 1011 C/kg >> 108 C/kg, either the electron has a far greater charge than the proton, or it has far less mass. • e/m for electron = 1.2 × 1011 C/kg, e/m for proton = 108 C/kg. I-17
The Person Behind The Science Robert Millikan 1868-1953 Highlights Appointed Director of the Norman Bridge Laboratory of Physics,Caltech(1921) Received Nobel Prize in Physics(1923) ● Worked on experimental aspects of photoelectric effect Moments in a Life Became a professor at the University of Chicago (1910) Performs his famous oil drop experiments(1909) -18
The Person Behind The Science Robert Millikan 1868-1953 Became a professor at the University of Chicago (1910) Performs his famous oil drop experiments (1909) Moments in a Life Highlights Appointed Director of the Norman Bridge Laboratory of Physics, Caltech (1921) Received Nobel Prize in Physics (1923) Worked on experimental aspects of photoelectric effect I-18