Charge Quantization

The Physics Hypertextbook™
© 1998-2008 by Glenn Elert -- A Work in Progress
All Rights Reserved -- Fair Use Encouraged

prev | up | next

---

Discussion

introduction

Robert Andrews Millikan (1865-1953) United States

apparatus

[magnify]

findings

[magnify]

Summary

• bullet

Problems

practice

1. Write something.
   • Answer it.
2. Write something.
   • Answer it.
3. Write something.
   • Answer it.
4. Write something completely different.
   • Answer it.

statistical

1. millikan.txt
   The data in this file show the charge on an oil drop determined by Millikan during one particular run of his famous experiment (1911). What value for the elementary charge, e, can be deduced from this data? Show the work used to arrive at your answer. Source: Halliday, David & Robert Resnick. Physics: Parts 1&2. 3rd Edition. New York: Wiley, 1978: 600.
2. oil-drop.txt
   The data in the accompanying text file were adapted from an article written by Millikan in 1911 for the Physical Review (Vol. 32: p. 349). The first column gives the trial number, the second column gives the battery voltage, and the last two columns give the time for the oil drop to fall down and then rise up between the cross hairs on the observing window. The table below provides the additional data needed to complete this assignment.
   
   

   Constants in Millikan's Experiment
   quantity	value
   distance between charged plates	1.600	cm
   distance between cross hairs	1.010	cm
   viscosity of air at 25.2 °C	18.36	μPa·s
   density of air at 300 K	3.556	kg/m3
   density of oil at 25 °C	896.0	kg/m3
   acceleration due to gravity	9.81	m/s2

   
   Using a spreadsheet program or similar data analysis software, determine the values of the following quantities and add them to the table.
   1. the speed of the drop on the way down
   2. the speed of the drop on the way up
   3. the radius of the drop
   4. the mass of the drop
   5. the strength of the electric field
   6. the charge on the drop
   7. the number of elementary charges
   8. the magnitude of the elementary charge

Resources

• general
  • The Mechanical Universe and Beyond (video on demand, login required)
    • The Millikan Experiment, A dramatic recreation of Millikan's classic oil-drop experiment to determine the charge of a single electron.

---

prev | up | next

Another quality webpage by Glenn Elert

home | contact bent | chaos | eworld | facts | physics