E photon
 hf
 hc

E
 hf

E
0

K max
 eV stop
P

E total
/t E total

NE photon
  h mv
E n
 n 2 h 2
8 mL
2
, n

1, 2, 3,... E h
  
34    
15    n

E m
 hc hf
 mn
 
7
Example 28.1
Electrons in a photoelectric effect experiment emerge from a copper surface with a eV
 m maximum kinetic energy of 1.10 eV. (a) Draw a picture of the situation. (b) What is the wavelength of the light?
Example 28.2 a. Your eyes have three different types of cones with maximum absorption al 437 nm,
533 nm, and 564 nm. What photon energies correspond to these wavelengths? b. Station KAIM in Hawaii broadcasts on the AM dial at 870 kHz, with a maximum power of 50,000 W. At maximum power, how many photons does the transmitting antenna emit each second?

Example 28.3 a. Rubidium atoms are cooled to 0.10 μ K in an atom trap. What is their de Broglie wavelength? How many times larger is this than the 0.25 nm diameter of the atoms?
What does the de Broglie wavelength mean in this case? b. What is the kinetic energy, in eV, of an electron with a de Broglie wavelength of 1.0 nm?
What does the de Broglie wavelength mean in this case?
Example 28.4
The allowed energies of a quantum system arc 1.0 eV, 2.0 eV, 4.0 eV, and 7.0 eV. a. Sketch an energy-level diagram for this quantum system. b. How many line emissions are possible? What wavelengths appear in the system's emission spectrum? Which lines are in the visible spectrum and rough what is the color? (380 nm < λ visible
< 750 nm)
Example 28.5 a. An electron confined in a one-dimensional box emits a 200 nm photon in a quantum jump from 1 = 2 to n = 1. What is the length of the box? b. A proton confined in a one-dimensional box emits a 2.0 MeV gamma-ray photon in a quantum jump from n = 2 to n = 1. What is the length of the box?