Silicon, Circuits, and the Digital Revolution
Atomic Units of Energy
- In our study of electricity we measured energy in units of kW-hr (kilowatt-hour).
- In atomic physics and semiconductor physics, we find that the eV (electron-volt)
is a convenient unit for measuring energy of photons and electrons.
- Relationship between kW-hr and eV; eV and joule?
- A watt-second is also an acceptable unit for energy, having the
same dimensions as kilowatt-hour. The watt-second is more commonly
known as a joule (J).
- A 1 kg (kilogram) mass held overhead has about 20 J of potential
energy relative to the floor; that is, when it hits my toe, it
will be carrying 20 J of kinetic energy.
- The electron-volt is the change of energy experienced by an electron
when it is relocated from one point to another, when the two points
have a 1.0 V difference.
- The electron-volt is a small quantity compared to the joule:
1.0 eV = 1.60 x 10-19 J
The Visible Spectrum
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Last updated April 14, 2000.
© George Watson, Univ. of Delaware, 2000.