Turn voltage on/off when you hear warning sound (if you
did not turn on "auto" mode)
The oil will drop down due to gravity and reach terminal velocity (v1).
Please turn on voltage when oil almost reach the bottom of the plate (click the
"Voltage on/off" checkbox at the lower left corner of the applet)
The oil drop will move up and reach another terminal velocity (v2).
From v1,v2 and Volateg you can calculate the charge on the oil drop (may be 1-5
electron --assigned randomly)
You can change the voltage between parallel plate, and you will get different
terminal velocity v2, and voltage U. But the calculated value for the charge
will be the same).
Click "change Q" will change the number of electron on the oil drop.
Click "new drop" will create another oil drop (different size and different
charge).
If you click auto, the simulation will turn on/off voltage automatically.
You can control it using JavaScript. For example, using buttons: