Accurate measurement experiment of element charge
American experimental physicist Robert Andrew Millikan
(Robert Andrews Millikan, 1868 ~ 1953) designed the oil drop experiment: two horizontally placed metal plates were connected to the positive and negative poles of the power supply respectively, so that the two metal plates were charged with different charges. A sprayer is used to eject charged oil droplets. When the charged oil droplets enter between the two plates, the voltage is adjusted to balance the electric field force and gravity of the oil droplets, from which the charge of the oil droplets can be obtained.
In 1910, he made improvements for the third time, so that the oil droplets can move up and down when the electric field force and gravity are balanced, and when irradiated, they can also see the sudden change of oil droplets due to the change in electricity, and then find The difference in the amount of charge change; in 1913, he obtained the value of the electronic charge: e = (4.774 ± 0.009) × 10-10esu, (usually taken e = 1.6 × 10-19C) Confirm the existence of elementary charge. The exact value he measured finally ended the debate about the dispersion of electrons, and made many physical constant calculations to a higher accuracy.
Millikan won the Nobel Prize in Physics in 1923 for his outstanding achievements in measuring the charge of electrons.