Source:
[1] Wikipedia Contributors. “Photoelectric Effect.” Wikipedia, Wikimedia Foundation, 8 Nov. 2020, en.wikipedia.org/wiki/Photoelectric_effect. Accessed 16 Nov. 2020.
[2] Khan Academy Organic Chemistry. “Photoelectric Effect | Electronic Structure of Atoms | Chemistry | Khan Academy.” YouTube, 25 June 2014, https://www.youtube.com/watch?v=vuGpUFjLaYE. Accessed 16 Nov. 2020.
[3] pixy.org. “Lichtspiel Optics Light Blue Gold Image.” Pixy.org, 16 July 2020, pixy.org/5948017/. Accessed 16 Nov. 2020.