Misconceptions In Photoelectric Effect

Photoelectric Effect Misconceptions and Questions Asked By Students

  Both my classes started on the photoelectric effect tutorial last Friday.  As the students were presenting their summaries to the rest of the class for one of my classes, one of the girls suddenly turned and asked me, "Why do the photoelectrons emit with different kinetic energy?".  Today, I went into my GATE class and during group discussions, I not only picked up this question from a student to another friend and other question related to the same idea.  Hm....to help me and other teachers who may be teaching the topic, I decided to document them down here. 

  Questions/Comments made by students:

1.  "Why do photoelectrons ejected from the metal with different kinetic energies?"

2.  "So does each electron in the metal have their own workfunction?"

3.  " The electrons are each in a different shell and hence they will require a different energy of emission".

4.  "But we just did line spectra in lecture, so are you saying that the electrons are excited?  And hence at different energies?  But if all the electrons are at ground state then would they be at the same energy level?"

5.  "So workfunction and ionisation energy is the same?  Because they are the minimum amount of energy to liberate an electron? "

I guess what I will do is that I shall flash all these comments on the board for discussion on Wednesday and I guess that should generate some interesting discussions for the class.  :)