Question

RA Millikan during his oil-drop experiment on electron found that the charge on an oil drop is

• A. a fraction of $1.6\times 10^{-19}C$
• B. an even multiple of $1.6\times 10^{-19}C$
• C. an odd multiple of $1.6\times 10^{-19}C$
• D. an integral multiple of $1.6\times 10^{-19}C$

Answer 1

Answer: (D)

It is found that the charge on an oil-droplet was always an integral multiple of an elementary charge, $1.6\times 10^{-19}C$. Millikan's experiment established that electric charge is quantised. From the values of charge $(e)$ and specific charge $(e/m)$, the mass $(m)$ of the electron could be determined.