This Is an Apparatus for Studying the Photoelectric Effect

Multiple Choice

This is an apparatus for studying the photoelectric effect. The work function of the material being investigated is 3.8 * 10^-19 J. Light of a wavelength 350 nm is incident on the material. What is the lowest voltage needed between the cathode C) and the anode A) to stop any electrons ejected from the cathode from reaching the anode?

A) 2.37 V
B) 1.17 V
C) 3.54 V
D) 4.71 V
E) None of these is correct.