A Photocathode Having a Work Function of 2

Multiple Choice

A photocathode having a work function of 2.8 eV is illuminated with monochromatic electromagnetic radiation whose photon energy is 4.0 eV.What is the threshold (cutoff) frequency for photoelectron production? (1 eV = 1.60 × 10^-19 J,h = 6.626 × 10^-34 J ∙ s)

A) 6.8 × 10¹⁴ _Hz
B) 2.9 × 10¹⁴ _Hz
C) 7.7 × 10¹⁴ _Hz
D) 8.6 × 10¹⁴ _Hz
E) 9.7 × 10¹⁴ _Hz