You are here:

Physics/Photoelectric vs Compton effect


I want to know when does the photoelectric effect happens and when does the Compton effect occur for one material. By this I mean, are there any SPECIFIC conditions that should be met for the photo elec or compt effect to be observed.
For example my textbook had two separate questions where the same piece of bone underwent both the effects and asked me to calculate momentum, wavelength etc  but it did not state why such thing happened! I want to know , if I let light of certain frequency on a bone will I see the Compton effect , or the photoelectric effect?

The photo-electric effect (PeE) occurs ONLY for VERY specific materials -- basically semiconductors. You will NOT see the PeE in any organic materials.

In addition, the PeE is only seen for UV, visible, and IR radiation. Photons of lower frequency do not have enough energy to knock an electron away from a metal; photons of higher frequency are not absorbed by an atom, they are more like high energy billiard balls.

The Compton Effect, on the other hand, occurs ONLY with x-rays. Photons of lower frequency are absorbed by atoms, and thus do not "bounce" off electrons like a billiard ball; photons of higher frequency simply go through materials without much angular change.

Thus, the choice is relatively simple: you only see Compton Effect with x-rays; you only see PeE with visible light on some metals.


All Answers

Answers by Expert:

Ask Experts




I can help with understanding physics that does not involve eggs. I will NOT help with academic or professional questions, which are NOT limited only to homework. Please do not waste your time by asking a question that comes out of ANY kind of academic, professional, or business matters.


Have been fascinated by physical laws ever since I learned, at age seven, that magnets work under water. My study continued through college and has not ceased even after I retired.

B.A. in Physics (with honors) from University of California at Berkeley.M.A. in Physics (with honors) from University of Texas Austin.

©2016 All rights reserved.