Answer the following question:
Quarks inside protons and neutrons are thought to carry fractional charges [( + 2/3)e ; (–1/3)e]. Why do they not show up in Millikan’s oil-drop experiment?
Quarks inside protons and neutrons are known to have fractional charges. Quarks do not show up in Millikan's oil drop experiment as these fractional charges do not exist independently, rather held together by strong nuclear force. These fractional charges are not found free in nature.