Quantum Physics Flashcards
What are the 2 possible explanations for the photoelectric effect?
- Classical wave model
2. Quantum model
How does the classical wave model define EM induction?
EM induction is a wave
How does the Quantum model define EM induction?
EM radiation is a particle known as photons - which are discrete packets of quantum energy of EM radiation.
How does the classical model describe the energy of EM radiation?
The energy of EM radiation is continuous.
How does the quantum model describe the energy of EM radiation?
It is discrete and can be calculated using Planck’s equation.
How does the classical model describe the release of photoelectrons?
Photoelectrons will only be emitted after a time interval or delay as the electrons gradually receive energy to escape the metal surface.
How does the Quantum model describe the emission of photoelectrons?
Photoelectrons are emitted instantaneously - no photoelectrons are emitted if the incident photons are not at the right frequency.
How does the classical model describe the kinetic energy of the photoelectron released?
As the intensity of the EM radiation increases, the photoelectron receives more power and their maximum kinetic energy increases.
How does the Quantum model describe the energy of the electrons released?
increasing the frequency of the incident EM radiation, more energy, so more kinetic energy.
increasing the intensity only increases kinetic energy.
What kinds of metals are used in the photoelectric setup?
Metals that release the electrons easier.
What is threshold frequency?
It is the minimum frequency for the incident photon for the photoelectron to be emitted from the metal surface.
What is the threshold wavelength?
It is the maximum wavelength of the incident photon for photoelectron to be emitted from the metal surface.
What is the work function energy?
It is the minimum energy of the incident photon for the photoelectron to be emitted from the metal surface.
How does the ammeter reading vary in the photoelectric cell?
For +tive v - there will always be reading on the ammeter
for a 0 v - there will be a drop
For -tive v - there will be almost no current reading
What is stopping potential?
It is the minimum pd necessary to stop an electron flow in a photocell/ stop the most energetic electron.
