PHYS.9.A

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The student is expected to describe the photoelectric effect and emission spectra produced by various atoms and how both are explained by the photon model for light;
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Knowledge and Skills Statement

Science concepts. The student knows examples of quantum phenomena and their applications.

There are two variations of the photoelectric effect.   

The Photoelectric Effect - electron ejection (a) and fluorescent X-ray emission (b).
Image 1 url:File:PhotoelectricEffect.jpg - Wikimedia Commons


a) In the image labeled (a), a photon collides with an electron, transferring energy. If the threshold frequency is met, the electron is ejected. This is better illustrated in the image below.

photoelectric effect for different wavelengths
Image 2 url:  File:Photoelectric-effect.svg - Wikimedia Commons


b) In the image labeled (b), a photon collides with an electron, sending the electron up an energy level. When the electron returns to its regular, lower-energy state, it emits a photon at a specific frequency with a specific amount of energy. The frequency and amount of energy can be calculated and predicted, as illustrated in the image below.
 

The 1913 Bohr model of the atom showing the Balmer transition from n=3 to n=2.
Image 3 url:  https://commons.wikimedia.org/wiki/File:Bohr_atom_model.png

the discrete wavelengths emitted by an atom or compound stimulated by heat, light, or electric current; unique to each element or compound

the emission of free electrons from a metal surface when light of an adequate (threshold) frequency strikes it

Research

Sayer, Ryan, Alexandru Maries, and Chandralekha Singh. "Quantum Interactive Learning Tutorial on the Double-slit Experiment to Improve Student Understanding of Quantum Mechanics." Physical Review Physics Education Research 13, no. 1 (2017): 010123. https://doi.org/10.1103/PhysRevPhysEducRes.13.010123

Summary:  The authors investigated student difficulties with quantum mechanics pertaining to the double-slit experiment in various situations that appear to be counterintuitive and contradict classical notions of particles and waves. Here they discuss the development and evaluation of a research-validated Quantum Interactive Learning Tutorial (QuILT) which makes use of an interactive simulation to improve student understanding of the double-slit experiment and strives to help students develop a good grasp of foundational issues in quantum mechanics.