3.2.2.1 - The Photoelectric Effect Flashcards
What is the threshold frequency?
Minimum frequency required to eject photoelectrons.
What kinetic energy do the photoelectrons have when emitted?
A variety of kinetic energies ranging from 0 to the maximum value.
When does the maximum value of the kinetic energy increase?
With the increase of frequency of the radiation.
When does the KE of the photoelectrons not increase?
When the intensity of the radiation is increased.
What does the intensity of the radiation affect?
The number of photoelectrons emitted per second.
E =
hf = hc/λ
What is the work function?
The minimum energy required to remove an electron from the surface of the metal.
Threshold frequency =
Φ/h
What is the energy transferred to an electron?
hf
What is hf =
Φ + Ekmax
KE =
1/2mv^2
eVs =
Ekmax
What is meant by the photoelectric effect?
The emission of electrons from a metal surface when electromagnetic radiation (or ultraviolet radiation, or light) is incident upon it
What does light consist of?
Photons which have energy hf.
What is photoelectric emission?
The emission of electrons from a metal surface when light is directed at the surface.
What does the electron have to gain in order to be able to leave the surface of the metal?
Energy equal or above the work function of the metal.
What does the frequency of the incident have to be above in order to provide the energy for the electron to leave the surface of the metal?
Φ/h (threshold frequency)
Why the emitted electrons have a range of kinetic energies up to a maximum value?
Photons have energy dependent on frequency. One-to-one interaction between photon and electron. Max KE = photon energy - work function. More energy required to remove deeper electrons.
