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Physics- quantum mechanics Exam with complete solutions 2024_2025
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Physics- quantum mechanics Exam with complete solutions 2024_2025
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Physics- quantum mechanics Exam withcomplete solutions 2024/2025
Electrons display characteristics of both - ANSWER-waves or particles
quantum mechanics - ANSWER--is the branch of physics that describes electrons
position within an atom (which we don't really know but can predict the
probability)
electrons - ANSWER--don't really have a "position" per se, but occupy different
energy levels based on the proximity to the nucleus
-acts like a standing wave most of the time, but acts like a particle at the crest of
the wave
-this explains why so little of the energy put into the x-ray system results in
photon production. It is random probability that incoming electron from the
cathode would interact with any particular electron within the anode target
wave like properties of an electron - ANSWER-1) the electrons do not orbit the
nucleus in the manner of a planet orbiting the sun, but instead exist as standing
waves
-Thus, the lowest possible energy an electron can take is similar to the
fundamental frequency of a wave on a string
-higher energy states are similar to harmonics of that fundamental frequency
2) the electrons are never in a single pont location, although the probability of
interacting with the electron at a single point can be found from the wave function
of the electron
, -the charge on the electron acts like it is smeared out in space in a continuous
distribution, proportional at any point to the squared magnitude of the electrons
wave function
Particle like properties - ANSWER-1) the number of electrons orbiting the nucleus
can only be an integer
2) electrons jump between orbitals like particles
-for example, if a single photon strikes the electrons, only a single electron
changes states in response to the photon
3) the electrons retain particle like properties such as: each wave state has the
same electrical charge as its electron particle. Each wave state has a single
discrete (spin up or spin down) depending on its superposition
are electrons particles or waves? - ANSWER--conducted with electrons instead of
lights, the 2 slit experiment demonstrated that beams of electrons can also
collectively interfere with each other
electrons as particle/waves - ANSWER--experiments confirmed that subatomic
particles have associated wave functions, and sometimes behave like waves
-supplemental:
this agreed with Einsteins equation (E=mc^2) showing that matter is a form of
energy, and plancks formula (E=hf) showing that high energies are associated
with high frequencies, which in turn represent short wavelengths
-the mass of an electron has an associated wave function with an assigned
wavelength and frequency (f=mc^2/h)
when electrons act like particles and when they act like waves depends on what?
- ANSWER--the way they are observed, i.e, the particular experiment conducted
-the entire subatomic world consists of "particle waves" that can be laid out in a
spectrum of energy levels
Wave mechanics - ANSWER--the motion of the electron is described by
mathematics that describe wave motion
-the energy/position of an electron is described by a probability distribution
(Fermi-Dirac Statistics)
heisenberg uncertainty principle (wave mechanics) - ANSWER--the closer we
know the momentum of the electron, the larger the uncertainty in the position of
the electron triangle(z)triangle(p)=h
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