Photoelectric Effect Flashcards
What is the Photoelectric Effect?
It is the emission of free electrons on the surface of the metal once a high frequency light shines onto it
What are the steps of the Photoelectric electron emission?
1) Free electrons on the surface of the metal absorb energy from the light
2) Once enough energy is absorbed the bonds holding it to the metal break and electrons are releases
3) This is the photoelectric effect and the free electrons and called photoelectrons
What are the conclusions?
1) If the threshold value of the radiation is below a certain value photoelectrons are NOT emitted
2) The number of photoelectrons emitted per second is proportional to the intensity of the radiation
Why cant the Photoelectric Effect be explained through wave theory?
The higher the intensity of the wave the more energy it should transfer to each electron- the kinetic energy should increase with intensity. there is no explanation for the kinetic energy. theres also no explanation for the threshold. according to wave theory the electrons should be emitted eventually no matter what the frequency is
What can the Photoelectric Effect be explained by?
Photon model of light
What is the equation for the energy carried out by a photon?
E=HF=HC/λ
if energy gained by an electron is greater than the work function what happens?
the electron is emitted
What is the equation for Threshold frequency?
f=ø/h
What is the equation for the maximum kinetic energy ?
hf = ø + Ek(max)
How do you work out Ek(max)?
1/2mv^2
How to work out stopping potential?
eVs = Ek(max)
