8/13/2019 Discharge Lamps Homework

1/2

Discharge Lamps Homework Activity

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

or this problem! yo" will be investigating the Discharge Lamps #im"lation .

a. $% pts& '.% each( Begin by exploring the )*atom panel and the +onfig"rable Atom. $Afew non*obvio"s sim"lation controls: ,o" can select the - of empty electronic energylevels in the config"rable atom and ad "st their location. And yo" can move the atomabo"t in the discharge t"be.( +onsider the following /r"e0 alse statements:

/r"e alse 1f the spacing between two electronic energy levels in atom A islarger than in atom B! then the wavelength of the light emitted by atom B will be longer.

/r"e alse 1f the spacing between two electronic energy levels in atom A issmaller than in atom B! then fewer photons will be emitted by atom B.

/r"e alse 2hotons are emitted as electrons in the atom "mp "p in energy/r"e alse /he colors emitted by an atom depends on how m"ch kinetic

energy the free electron has when it hits the atom

/r"e alse /he colors emitted depends on the n"mber of free electrons passing thro"gh the lamp.

/r"e alse 3hen a free electron hits an atom! the atom is always excited tothe highest energy level possible.

/r"e alse /he kinetic energy of the free electron at the point of collisionincreases as the voltage of the battery increases.

/r"e alse /he kinetic energy of the free electron at the point of collision ishigher if the atom is closer to the so"rce of electrons

/r"e alse /he only way to emit 14 photons is if there are empty electronicenergy levels really close to the gro"nd state $lowest energy level(.

/r"e alse 3hen atomic electrons are excited to a higher level! they alwaysret"rn to their lowest energy level by "mping down one level at a time.

b. $'.5 pts( How many possible colors can an atom with 6 electronic energy levels$Gro"nd state thro"gh level 5( emit7

c. $essay( 1n some discharge lamps! the work f"nction of the metal cathode is overcome by heating the electrons so they have eno"gh thermal energy to get o"t. /he voltagedifference across the plates then give these electrons a certain amo"nt of electrostatic

potential energy. As always! energy m"st be conserved. /rack and explain the transfersand conversions between different forms of energy that occ"r in a discharge lamp thatmake it work to prod"ce light. Be s"re to incl"de the main physics ideas abo"t how atoms

http://www.colorado.edu/physics/phet/dev/fluorescent-lights/1.00.03/dischargelamps.jnlphttp://www.colorado.edu/physics/phet/dev/fluorescent-lights/1.00.03/dischargelamps.jnlp

8/13/2019 Discharge Lamps Homework

2/2

behave which are needed to make sense of what8s going on.