 #1
Shaye
 19
 7
 Homework Statement:

A tiny negatively charged oil drop is held stationary in the electric field between two horizontal parallel plates, as shown below (please see attachment). Its mass is 4.0x10^15kg.
Question 15,b) Use the fact that the 2 forces balance to calculate the charge on the oil drop. (g = 10 N Kg^1).
 Relevant Equations:

1. F  Ma
2. E = F/Q or E = V/D (Electric field strength)
The book gives an answer of Q = 3.2 x 10^19C
I get an answer of 6.67 x 10^19C. Workings below:
I get an answer of 6.67 x 10^19C. Workings below: