Nuclear & Particle Physics - Photoelectric

Questions 31-33  refer to the apparatus used to study the photoelectric effect (see GR8677 #31).
The quantity W in the photoelectric equation is the

1. Energy difference between the two lowest electron orbits in the atoms of the photocathode
2. Total light energy absorbed by the photocathode during the measurement
3. Minimum energy a photon must have in order to be absorbed by the photocathode
4. Minimum energy required to free an electron from its binding to the cathode materials
5. Average energy of all electrons in the photocathod

(GR8677 #33)

Solution:

Einstein photoelectric equation: |eV| = hv −W

eV = kinetic energy of the electron as it accelerates through the medium between the cathode and collector
W = work function; energy to free the electron from the metal
hv = energy given by the light source.

Answer: D