Lithium was one of the metals studied by the American physicist Robert Millikan in his research on the photoelectric effect. When illuminated with blue light of frequency 6.64 × 10 14 Hz, the photoelectrons ejected from a lithium surface have a maximum kinetic energy of 0.332 eV. What is the threshold frequency for lithium? For this problem, let the value of Planck's constant, h, be 6.63 × 10 -34 J·s.