Exam Flashcards
What did Max Planck suggest in 1900?
Suggested that quanta of energy are absorbed by and emitted from matter
What two assumptions did Max Planck have?
1) The emitted radiation of frequency v = c/λ was produced by a group of atoms in the solid that oscillate with that same frequency
2) The energy of oscillation for a particular group of atoms was restricted to certain special values given by E(osc) = nhv, and h is a constant to be determined.
Who was the first to suggest the quantization of energy?
Max Planck
What does the photoelectric effect prove?
It proves that light can produce an electric current
What three observations were noted when studying the photoelectric effect?
1) electrons were ejected only if the frequency of light was greater than some “threshold” frequency, v(ø)
2) For v _> v(ø), the KE of an ejected electron increased proportionally with v
3) provided v _> v(ø), electrons were ejected instantaneously regardless of the intensity of the incoming light
The slope a line between v(ø) and v is the first experimental evidence of…
Plank’s constant (h)
What did Einstein propose about the photoelectric effect? (2)
- That energy of light cannot be spread out over the entire wave, it must be concentrated into small, particle like bundles (i.e. photons)
- The energy of a photon must be proportional to the frequency of the light
What was the final proof that energy is quantized?
The line spectra of atoms (shown by the dispersion of white line through a prism)
What did Louis de Broglie state?
Light could exhibit wave-particle dualities
What does the Heinsenberg uncertainty principle state?
It is impossible to know simultaneously both the position and the momentum of a particle with absolute certainty.
- We should focus on “what is the most probable behaviour” instead of
The smaller the uncertainty of a particle’s position, the ______ the uncertainty of the particle’s momentum.
greater
In the Schrödinger equation, ____ is a mathematical function that depends on the coordinates (x,y,z)
Ψ (psi)
d2 Ψ / dx2 is the _________ of Ψ with respect to x.
second derivative
Does and Ψ and | Ψ |2 both have physical interpretations?
No, just | Ψ |2
What does | Ψ |2 state?
1) the probability of finding the e- within a small region of volume dV near the point (x,y,z)
2) the density of the e- “cloud” contained within a small region of volume dV near the point (x,y,z)
