Name:
________________
ANSWERS
______________
PHYS1200
PHYSICS II
SPRING 2005
Class 23 Activity: Bound Electrons Finite Well versus Infinite Well
Because the wave function of an electron can protrude beyond the walls of a finite well but
cannot for an infinite well, the expressions for energy levels are different for each case.
The objective here is to calculate energy levels for an infinite well for various states, and then
compare them to the energy levels for a finite well that your computer will calculate.
•
Write down the expression for the energy levels for an electron that is bound in a one
dimensional
infinitely
deep potential energy well that is 2.0 nm wide.
E
n
=
2
2
2
8
n
mL
h
for
n
= 1, 2, 3, 4,….
•
What is the value for
h
, and what is its value?
Planck's Constant.
h = 6.63 x 10
34
Jouleseconds
•
What is
m
, and what is its value?
Mass of the particle, in this case the electron.
m = 9.11 x10
31
Kg
•
What is
L
and what is its value?
Width of the well.
L = 2.0 nanometers in this case
•
What is
n
?
Quantum number.
n = 1,2,3 or 4 for this case.
Calculate the energies of the first four energy levels in the infinite well (i.e.
n
= 1, 2, 3, and 4),
and record them in Joules, then convert that answer to electron volts ….
Then, determine what the wavelength of the electron will be in each state for the infinite well.
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 Spring '08
 PeterPersans
 Physics, Energy, Kinetic Energy, Photon, 2.0 nanometers

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