• Robert Millikan used his oil drop experiments to deterine the magnitude of an electron's charge

<aside> 📌 The elementary charge, $e$, is equal to $1.602 * 10^{-19}C$ and represents the electric charge carried by a proton. It is also the absolute balue of electric charge carried by an electron

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The value of the charge on an electron is $-1.602 * 10^{-19}C$

• Every subatomic particle so far detected has charge whose magnitude is equal to whole-number multiple of the elementary charge

1.) r = 110cm = 1.1m

N = 1.2*10^8

e = 1.602*10^-19

k=8.99N