13.2-13.3 Photoelectric Effect Quizlet Cards Flashcards
How can the threshold p.d. of an LED be used to find photon energy?
The energy transferred by the electrons (e x V) is equal to the energy of the photons produced (hf).
What is the photoelectric effect?
The emission of electrons from a metal surface when illuminated with light.
What is the atomic structure of a metal?
A lattice of positive ions surrounded by a sea of free electrons.
What is a photoelectron?
An electron that has been removed from a metal by absorbing a photon
What is the work function?
The minimum energy required to remove an electron from the surface of a metal
What is the threshold frequency?
The minimum frequency of light required to produce photoelectrons from a metal
What is monochromatic light
Light of a single frequency/wavelength
What is the relationship between work function and threshold frequency?
∅ = hf₀
What is required for a photon to be able to produce photoelectrons?
Its frequency is greater than the threshold frequency
Why can’t light sources below the threshold frequency produce photoelectrons?
The photon energy is less than the work function
How do photons and electrons interact?
A single photon can be absorbed/emitted by a single electron which gains/loses the energy of the photon.
What is the effect on an electron of absorbing a photon?
The electron gains the energy of the photon
What effect does increasing the frequency of a monochromatic light source have on photoelectrons produced?
Photoelectrons will have a greater maximum kinetic energy
What is the effect of increasing the intensity of a monochromatic light source on photoelectrons produced?
More photoelectrons will be produced but they will have the same maximum kinetic energy
Why does the kinetic energy of photoelectrons from monochromatic light vary in the photoelectric effect?
The work function is a minimum energy. Some electrons are liberated from deeper into the metal and require more energy to be liberated.
What two factors that determine the maximum kinetic energy of photoelectrons?
The frequency of the light and the work function of the metal
What determines the rate at which energy is delivered by a wave?
Intensity/amplitude of the wave
What is hf in Einstein’s photoelectric effect equation (hf = 𝜙 + KE(max))
The energy of the incident photon.
What is 𝜙 in Einstein’s photoelectric effect equation (hf = 𝜙 + KE(max))
The work function of the metal
What is KE(max) in Einstein’s photoelectric effect equation (hf = 𝜙 + KE(max))
The maximum kinetic energy of the photoelectrons
According to the wave model how is energy transferred from light to electrons in a metal?
It is delivered continuously and builds up over time
If light is above the threshold frequency, how long will it take for photoelectrons to start being produced?
It is instantaneous
