The work function for a copper surface is 7.3 x 10⁻¹⁹ J. If photons with an energy of 9.9 x 10⁻¹⁹ J strike the copper surface, the maximum kinetic energy of the photoelectrons in joules will be?
a. 2.6 x 10⁻¹⁹
b. 4.0 x 10⁻¹⁹
c. 5.9 x 10⁻¹⁹
d. 7.3 x 10⁻¹⁹