Quantum Physics Flashcards
What did max planck discover?
Electromagnetic energy exists in certain values( tiny packets called Qantas).
Electromagnetic radiation had a particular nature of being tiny packets of energy rather then a continuous wave.
What is the relationship between the energy of a photon and its frequency?
The energy of a photon is directly proportional to its frequency.
What is the equation for energy of a photon?
E=hf
h= planck constant
What is the relationship between the energy of a photon and its wavelength?
Energy of a photon is inversely proportional to its wavelength.
Shorter wavelengths have much more energy.
What unit do we use to measure energies at a quantum scale?
Electron volts eV
Define 1eV
The energy transferred to or from an electron that moves through a potential difference of 1V.
How do you convert from J to eV?
Divide by 1.6x10-19
Experiment to determine Plancks constant.
What is the photoelectric effect?
The emission of photoelectrons from a metal surface when electromagnetic radiation is above a threshold frequency is incident on a metal
What is a photoelectron?
An emitted electron
State 1 key observations of the photoelectric effect.
Photoelectrons are only emitted when the incident radiation is above the threshold frequency.
Will electrons be emitted if the intensity of the incident radiation is high?
Not if the frequency is less than the threshold frequency.
State the second key observation from the photoelectric effect.
If the incident radiation is above the threshold frequency, photoelectrons will be emitted instantly
State the third observation from the photoelectric effect
If the incident radiation is above the threshold frequency, increasing the intensity of the radiation does not increase the maximum kinetic energy of the photoelectrons.
What increases the maximum kinetic energy of a photoelectron?
Increasing the frequency of the incident radiation.
Shat type of interaction do photons and electrons have?
Each proton gad the exact energy to emit an electron in a one-to-one interaction
Define the work function.
The minimum energy required to free an electron from the surface of the metal
What does increasing the intensity if the radiation do?
More photons per second hit the metal surface. Meaning a grater rate if photoelectrons are emitted from the metal.
What is the relationship between the rate of emission of photoelectrons and the intensity of the incident radiation?
Rate of emission of photoelectrons are directly proportional to the intensity of the incident radiation.
What does the energy of a photon do?
- Its frees a single electron from the surface of the metal in a one-to-one interaction.
- Any remainder energy is transferred as kinetic energy for the photoelectron
What is the equation for energy of a single photon?
hf= Ek+ϕ
What is the relationship between a wavelength of a particle and its momentum?
The wavelength of a particle is inversely proportional to its momentum.
