일반물리학 2 — Electric Fields: Problem 33

33 In Millikan’s experiment, an oil drop of radius \( 1.64 \text{ }\mu\text{m} \) and density \( 0.851 \text{ g/cm}^3 \) is suspended in chamber C (Fig. 22-16) when a downward electric field of \( 3.20 \times 10^5 \text{ N/C} \) is applied. (a) Find the charge on the drop, in terms of \( e \). (b) If the drop had an additional electron, would it move upward or downward?