When did Heinrich Hertz discover the photoelectric effect and observe that shining ultraviolet light on the electrodes caused a change in voltage between them?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 1887.
Heinrich Hertz discovered the photoelectric effect and observed that shining ultraviolet light on the electrodes caused a change in voltage between them in 1887. Hertz's experiments demonstrated that ultraviolet light could cause an electric current to flow in a circuit, a phenomenon later explained by Albert Einstein in 1905, which contributed significantly to the development of quantum theory. Hertz's work laid the foundation for understanding the interaction between light and matter.