Millikan oil drop experiment

1. Sources: http://ffden-2.phys.uaf.edu/212_fall2003.web.dir/ryan_mcallister/slide3.htm
http://www.juliantrubin.com/bigten/millikanoildrop.html

MILLIKAN OIL-DROP EXPERIMENT - finding the value of q
By: Rangel Daroya, Aris Abigail Villaruel, Levy Tugade
IV-Electron
Recall:
q = 1.602 x
F = mg
F = qE

What Milikan did:
1. Measured the mass of the oil drop
2. Cause electrons to attach to the oil drop
 Using X-ray to ionize
 Rate of falling slows, because bottom plate is negative
3. Adjusted the voltage of battery to adjust electric field until oil drop stops moving
 Recall: E =
 F downwards = F upwards

 Higher voltage = higher electric field = oil droplets with more electrons stop moving

4. He observed his data and found out that all computed q’s were found to be a multiple of:
1.602 x
Questions: 1. What did Robert Milikan use to ionize the oil?
2. Which two equations did he mainly use to get the value of q?