Answer: 6.626 x 10 -34 J s.
- A 6.626 x 10<sup>-34</sup> J s
- B 6.626 x 10<sup>-23</sup> J/K
- C 9.1 x 10<sup>-31</sup> kg
- D 1.6 x 10<sup>-19</sup> C
Correct answer: A. 6.626 x 10<sup>-34</sup> J s
Explanation: h = 6.626 x 10<sup>-34</sup> J s. It is the fundamental quantum of action (energy x time).
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.