Sabyasachi Choudhury
Last Activity: 3 Years ago
I know it`s too late to help you know, but I`m still leaving this for anyone who might come here.First, take a look at this page - https://www.physicsclassroom.com/class/estatics/Lesson-2/Charging-by-FrictionHere, you`ll notice a think called electron affinity mentioned. Electron affinity, in a nutshell, is just the tendency of a material to take in an electron and hold on to it. High EF means it will absorb electrons, low means it will let a material with higher EF take its electrons.It is this electron affinity which determines which direction the electrons will move when you rub material X with material Y.You might also be wondering how to determine which materials have a higher EF than others. Now, I haven`t found a definitive answer to this from my scouring of the web, but I`ve noticed a pattern - when X and Y are rubbed, its always the one which is a better insulator (or worse conductor), which absorbs the electrons.In other words, higher resistivity = higher electron affinity.Now, I might very well be wrong here, and so feel free to correct me. I hope I could help anyone who comes across this post!