chapter  27

Charge Measurement

WithSaps Buchman, John T. Mester, T.J. Sumner

Electric charge, a basic property of elementary particles, is defined by convention as negative for the electron and positive for the proton. In 1910, Robert Andrews Millikan (1868–1953) demonstrated the quantization and determined the value of the elementary charge by measuring the motion of small charged droplets in an adjustable electric field. The SI unit of charge, the coulomb (C), is defined in terms of base SI units as