阿电磁学01-01：电荷 有京大摩 ▣1909年Robert Andrews Millikan(密立根)通过直接测量油滴电 荷，证实了电荷的量子性。 Atomizer Oil Droplets X-Ray Source Charged Metal (lonizing Radiation) Plate (+ -Microscope Charged Metal Plate (- The purpose of science is to Charged develop,without prejudice Oil Droplet or preconception of any kind,a knowledge of the facts,the laws,and the processes of nature. 口问题：尝试一下这个油滴实验？ -Robert A.Millikan
电磁学01-01: 电荷 1909年Robert Andrews Millikan (密立根)通过直接测量油滴电 荷，证实了电荷的量子性。 问题：尝试一下这个油滴实验？
可电磁学01-01：电荷 有京大整 Calculation of the oil drop charge Millikan used an electric field to balance gravity and suspend a charged oil drop: F,=eE=e与=-mhop8 d →e=-1 ldropgd/' Turning off the electric field,Millikan noted that the drop mass,could be determined from Stokes'relationship of the terminal velocity,v.to the drop density,p,and the air viscosity,n: Drop and radius: r=3nV,/2gp mhp=专元r3p Thousands of experiments showed that there is a basic quantized electron charge: e=1.602x10-19C
电磁学01-01: 电荷
窗电磁学01-01：电荷 有京大赞 ▣ 回顾Millikan:实验： >Millikan modified experiments tried by others and did very careful work. >Used nonvolatile oil rather than volatile water. Corrected equations for rate of fall of drop -determined this experimentally From Millikan's 1911 paper ▣ 须知条件： Q Q Nearby Divided (1)Density of air,(2)Viscosity of air, /×1018C /1.64×10-19 integer by6.02 (3)Density of oil,(4)Equation for -1.970 -12.02 -12 1.996 rate of fall,(5)Strength of electric -0.987 -6.02 -6 1.000 field,(6)Temperature,(7)Air Pressure -2.773 -16.93 -17 2.813
电磁学01-01: 电荷 回顾Millikan实验： Millikan modified experiments tried by others and did very careful work. Used nonvolatile oil rather than volatile water. Corrected equations for rate of fall of drop – determined this experimentally 须知条件： (1) Density of air, (2) Viscosity of air, (3) Density of oil, (4) Equation for rate of fall, (5) Strength of electric field, (6) Temperature, (7) Air Pressure Q /10-18 C Q /1.64 10-19 Nearby integer Divided by 6.02 -1.970 -12.02 -12 1.996 -0.987 -6.02 -6 1.000 -2.773 -16.93 -17 2.813 From Millikan’s 1911 paper
可电磁学01-01：电荷 有京大赞 ▣Millikan借助光电效应测量Planck常数： Ultra voilet rays KE KE=hf.中 slope =h Photo electrons frequency threshold frequency Photo electric emission Energy of electrons ejected from sodium metal h=Ab =4.1xl0-15eV-s Av △E=1.25eV The linear increase in △v=3.xl0 ons electron kinetic energy shows that whatever is The slope of the curve gave the constant of proportionality ejectingt hem has that we now call Planck's energy proportional constant. to frequency. 10 12 Frequency,Hz x1014 Data from Millikan,1916
电磁学01-01: 电荷 Millikan借助光电效应测量Planck常数：
闷电磁学01-01：电荷 有京大赞 ▣基本电荷e~1.60217733×10-19C le|≈|lh≈2c≈4.8xl010cm Structure within LTM Gaussian→L) the Atom Quark Electron le1≈8π Nucleus Neutron and -Proton -Atom e≈A姬e≈A亚 >So far so true e",us,Ac,are relativistic invariants > Basic particle physics >Never“seen”never“touched
电磁学01-01: 电荷 基本电荷 e ~ 1.6021773310-19C So far so true Basic particle physics Never “seen” never “touched”!