Chapter 7 Flashcards
Planck Constant x Frequency =
Energy
Photon-Energy equation.
E=hc/λ
Total energy transferred per second/Energy of single photon =
Number of photons emitted per second.
Explain the photoelectric effect.
The emission of electrons when a light of a sufficiently high frequency strikes a metal surface.
What does the kinetic energy of the emitted elecrtrons depend on?
The frequency of the light. the intensity only changes the number of electrons emitted.
What happens if the frequency of the light is lower than the “threshold frequency”? (Photoelectric effect)
No electrons will be released no matter how bright the light source.
What is the “work function” of a metal? (Photoelectric effect)
The amount of energy required to remove an electron from a metal surface.
The maximum kinetic energy of the ejected electron=
hf-Φ. Φ=work function
What happens when an electron falls from a higher energy level?
The atom releases a photon that has equal energy to the difference between the energy levels.
Φ/h=
Threshold frequency.
What number is the ground state given? (energy levels)
n=1
The De Broglie equation.
λ=h/p=h/mv
The frequency of an electron phasor=
Ekinetic/h. Ekinetic=1/2mv²
When do you get diffraction with an object?
When it interacts with an object about the same size as its De Broglie wavelength.
How do LEDs work?
An electron passes from one side to the other and as it does so it falls to a lower energy level and emits a photon. Diodes made from different semiconductors will release photons of different energy, which results in a different wavelength.
