Answer: 1.50 V.
- A 1.50 V
- B 0.80 V
- C 1.10 V
- D 0.50 V
Correct answer: A. 1.50 V
Explanation: Photon energy = 1240/400 = 3.10 eV. Therefore K<sub>max</sub> = 3.10 - 2.0 = 1.10 eV. Since eV<sub>0</sub> = K<sub>max</sub>, the stopping potential is 1.10 V.
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.