Sample Final Exam

Photoelectric Effect [22 Points]
When a photoelectric experiment is performed using calcium as the emitter,
the following data are observed.
λ (nm) 254 366
f (PHz) 1.18 0.82
V stop (V) 1.98 0.49
a) Using the above data, make a graph of KE max vs f. From the graph find
Planck’s constant h and the work function for calcium. [12 Points]
Answer: 6.62 x 10 -34 J∙s, 2.90 eV
b) Determine the cutoff wavelength and frequency for calcium. [6 Points]
Answer: 429 nm, 0.70 PHz
c) Find the maximum kinetic energy of the photoelectrons for λ = 200 nm.
[4 Points]
Answer: 3.30 eV