SCEN103 10/24 Class
Bottom of page/
Excited States and Quantum Leaps
of "Introduction to Atomic Physics"
- Excited States
- State of equilibrium, state of lowest energy,
is known as the ground state
- Higher energy states are known as excited states.
- with orbitals that are larger, with different shapes.
- Electrons can be promoted to higher orbits by:
- collisions with other atoms
- bombardment with electrons or other particles
- absorption of light...
- Light is emitted when atom relaxes to ground state from excited state.
- Light is electromagnetic radiation
- "pure" energy -- photons
- The electronmagnetic spectrum
- The visible
- Demonstrations of discharge lamp (with neon, hydrogen, and oxygen),
falling kg mass
Borrowed from the
Dept. of Physics of
- Quantum Leaps
- On careful examination, we find that light emitted by excited atoms
has discrete values of energy.
- Deduce that electrons in an atom have discrete values of energy.
- Energy levels of electrons in an atom are quantized.
Borrowed from OSM,
Office of Spectrum Management, of the
National Telecommunications and Information Administration.
Borrowed from The Tech
- 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
- Classification of Solids (continued!)
- Observe and test the four cylindrical samples provided.
- Try to identify as many physical attributes as possible
-- Be imaginative! I came up with about 10 different properties.
-- Included in each kit are several pieces of abrasive paper and a hard, steel bolt.
- Which classification categories would hold 2 each? which 3:1?
If time permits:
Adding "personality" to your account
Top of page/
- telnet to your account
- finger -- .plan
- Files starting with "." are normally hidden.
- Check distinction between finger ghw
and finger firstname.lastname@example.org
- Create or edit .plan with pico
- e-mail -- .signature
- Keep short: 4 lines is good
- Only information that you really want to share with everyone
- May be automatically attached to outgoing mail and newsgroup messages
- Modifying pine names
- Configuration file (.pinerc)
to change personal-name=
- Address file (.addressbook)
to change To: names
Back to SCEN103 Home Page.
Comments, suggestions, or requests to email@example.com.
Last updated Oct. 24, 1996.
Copyright George Watson, Univ. of Delaware, 1996.