Neon Lights & Other Discharge Lamps

This activity has been adapted from an activity by Sam McKagan, Kathy Perkins, and Carl Wieman licensed underCC-BY-4.0(phet.colorado.edu/en/contributions/view/2870)

Learning Goals: Be able to explain how a discharge lamp works and how energy is transferred in each process involved in a discharge lamps.

For this problem, you will be investigating theNeon Lights & Other Discharge Lampssimulation from the PhET Simulations program.

1.Begin by exploring the 1-atom panel and the Configurable Atom. (A few non-obvious simulation controls: You can select the # of empty electronic energy levels in the configurable atom and adjust their location. And you can move the atom about in the discharge tube.) Consider the following True/False statements:

a. If the spacing between two electronic energy levels in atom A is larger than in atom B, then the wavelength of the light emitted by atom B will be longer.

b. If the spacing between two electronic energy levels in atom A is smaller than in atom B, then fewer photons will be emitted by atom B.

c. Photons are emittedaselectrons in the atom jump up in energy.

d. The colors emitted by an atom depends on how much kinetic energy the free electron has when it hits the atom.

e. The colors emitted depends on the number of free electrons passing through the lamp.

f. When a free electron hits an atom, the atom is always excited to the highest energy level possible.

g. The kinetic energy of the free electron at the point of collision increases as the voltage of the battery increases.

h. The kinetic energy of the free electron at the point of collision is higher if the atom is closer to the source of electrons.

i. Theonlyway to emit IR photons is if there are empty electronic energy levels really close to the ground state (lowest energy level).

j. When atomic electrons are excited to a higher level, they always return to their lowest energy level by jumping down one level at a time.

2. How many possible colors can an atom with 6 electronic energy levels (Ground state through level 5) emit?