Answer: 3 eV.
- A 2 eV
- B 3 eV
- C 5 eV
- D 7 eV
Correct answer: B. 3 eV
Explanation: K<sub>max</sub> = E<sub>photon</sub> − work function = 5 − 2 = 3 eV.
In the photoelectric setup, light striking the metal plate ejects electrons that cross the evacuated tube to the collector, producing a measurable current on the ammeter.
Concept context
Photoelectric effect, de Broglie waves, Bohr's model, atomic spectra.