Question: We measure electrical charge in units of coulombs; a hundred years ago it was common to measure electrical charge in units called esu. The conversion is 3 × 109 esu = 1C.
a. What is the charge of the electron measured in esu?
b. Thomson measured e/m to have a value of 2.3×1017 esu/g. Convert this to C/kg and compare the result with the currently accepted value.
c. Why was Thomson the first to see cathode rays be deflected by an electric field?
Fig. - An oil drop suspended in an electric field.