In his famous 1909 experiment that demonstrated quantization of electric charge,

ID: 2001342 • Letter: I

Question

In his famous 1909 experiment that demonstrated quantization of electric charge, R. A. Millikan suspended small oil drops in an electric field.

Part A

With a field strength of 20 MN/C, what mass drop can be suspended when the drop carries a net charge of 10 elementary charges?

In his famous 1909 experiment that demonstrated quantization of electric charge, R. A. Millikan suspended small oil drops in an electric field.

Part A

With a field strength of 20 MN/C, what mass drop can be suspended when the drop carries a net charge of 10 elementary charges?

charge on drop q = ne = 10 x 1.6 x 10^-19 = 16 x 10^-19 C

E = 20 x 10^6 N/C

so electric force will be Fe = qE

when drop is in equilibrium,

then qE - mg = 0

(16 x 10^-19 x 20 x 10^6) = m x 9.81

m = 3.26 x 10^-12 kg