Physics Commons^™

Problem Set #1, David Peak

Problems

A little E&M practice

Problems 1-2 refer to: The electric field in a laser beam is given by E( x,t) = (1000V/m)sin[(πx10⁷rad/m) x + (3πx10¹⁵rad/s)t].

Problem Set #7, David Peak

Problems

Atom stuff

Problem Set #8, David Peak

Problems

A bit of stat mech

Problems 1-3 refer to: N identical, noninteracting, and distinguishable spin-1/2 particles (i.e., their separation is much greater than their de Broglie wavelength) are placed in an external magnetic field. Assume the ground state energy of one such particle is 0 and the excited state energy is ε , and the system is in thermal equilibrium at temperature T.

Problem Set #5, David Peak

Problems

Expectations & 1D finite wells

Problem Set #2, David Peak

Problems

A little energy and momentum practice (and units)

Problems 1-2 deal with “rest” energy and relativity.

Problem Set #9, David Peak

Problems

Another bit of stat mech

Problems 1-3 refer to: N identical, noninteracting, and distinguishable quantum harmonic oscillators (i.e., their separation is much greater than their de Broglie wavelength) are in thermal equilibrium at temperature T. The energy of each oscillator can be expressed as ε_n = nε , where ε is the level spacing and n = 0, 1, 2, … .

Schrödinger, 2, David Peak

Schrodinger

The finite square well

The infinite square well potential energy rigorously restricts the associated wavefunction to an exact region of space: it is infinitely “hard.” Potential energies encountered in more realistic physical scenarios are “softer” in that they permit wavefunctions to spread throughout less well-defined regions. An important toy example of the latter is the finite square well. In this problem, the potential energy function is U(x) = 0, if 0 < x < L, and U₀ otherwise.

Schrödinger, 3, David Peak

Schrodinger

The 3D infinite square well: quantum dots, wells, and wires

In the preceding discussion of the Schrödinger Equation the particle of interest was assumed to be “moving in the x -direction.” Of course, it is not possible for a particle to be moving in one spatial direction only. If that were true, according to the HUP it could be anywhere in the y - and z -directions and therefore be undetectable with finite volume detectors. Now, we consider the more realistic case of motion in all three spatial directions. For this purpose, we start with the 3D infinite square well. …

Schrödinger, 1, David Peak

Schrodinger

The Schrödinger equation: the quantum description of one massive, slow-moving particle

To establish a probability wave equation for one photon, it was useful to note that probability density and electromagnetic energy density were proportional. The governing equation for EM radiation fields is the Maxwell wave equation, which is also the governing equation for photon probability wave functions. Converting from EM radiation to photon information is made plausible by identifying energy and momentum operators with time- and space-derivatives, respectively. Thus, the Maxwell wave equation can be interpreted as being equivalent to the energy-momentum relation for photons. Though we don’t have a …

Schrödinger, 5, David Peak

Schrodinger

Transitions

Schrödinger, 4, David Peak

Schrodinger

The sanitized hydrogen atom: separating the variables

Separation of variables in the Schrödinger Equation for the hydrogen problem requires expressing Ψ as a product, Ψ(r,θ,φ,t) = R(r)Θ(θ )Φ(φ)T(t) , substituting into the partial differential equation [(5) in Sc3], and then dividing by Ψ. As in the square well problems, the separation constant for the t part of the separation is the particle’s eigen-energy, E.

Physics 2710: Introductory Modern Physics, David Peak

Syllabus

No abstract provided.

Foundations, 2, David Peak

Foundations

The double slit experiment in dim light – photons!

Let’s imagine doing the double slit experiment again, but now in very dim light. To do so requires putting the laser, plate, and collector in a sealed, light-tight box. Inserting neutral density filters in the beam between the laser and the double slit plate decreases the intensity of the beam striking the plate. In fact, the experiment can be done at such a low intensity that a human eye will not see any light on the CCD collector; but the CCD can. Under these conditions, the number of pixels that “light …

Many-Particle Systems, 10, David Peak

Many Particles

Intrinsic semiconductors

Intrinsic semiconductors have negligible concentrations of impurity atoms. Their electrical conductivity arises primarily from electrons excited into the otherwise empty conduction band from the otherwise filled valence band—usually by absorbing sufficient energy from phonons at finite temperature. Exciting an electron into the conduction band leaves a vacant state in the valence band. An electron at lower energy in the valence band can fill this vacant state. That, in turn, makes available a possible state for yet another valence band electron to fill. In other words, the excitation of the electron provides a mobile charge in the conduction band …

Physics 2710 – Example Exam Iii, David Peak

Exams

No abstract provided.

Physics 2710 – Example Exam Ii, David Peak

Exams

No abstract provided.

Physics 2710 – Example Exam I, David Peak

Exams

No abstract provided.

Physics 3710 – Exam Iii, David Peak

Exams

No abstract provided.

Physics 3710 – Exam Ii, David Peak

Exams

No abstract provided.

Physics 3710 – Exam I, David Peak

Exams

No abstract provided.

Evolution Of The Electron Yield Curves Of Insulators As A Function Of Impinging Electron Fluence And Energy, John R. Dennison, Alec Sim, Clint Thomson

All Physics Faculty Publications

Electron emission and concomitant charge accumulation near the surface of insulators is central to understanding spacecraft charging. A study of changes in electron emission yields as a result of internal charge buildup due to electron dose is presented. Evolution of total, backscattered, and secondary yield results over a broad range of incident energies are presented for two representative insulators, Kapton and Al₂O₃. Reliable yield curves for uncharged insulators are measured, and quantifiable changes in yields are observed due to <100-fC/mm² fluences. Excellent agreement with a phenomenological argument based on insulator charging predicted by the yield curve …

Solar- Terrestrial Physics: A Space Age Birth, R. W. Schunk

Faculty Honor Lectures

Solar- Terrestrial Physics, in its broadest sense, is concerned with the transport of energy, particles, and fields from the sun to the earth and their consequent effect on the terrestrial environment. Most of the solar energy eventually deposited in our atmosphere, at a rate of approximately a trillion megawatts, arrives in the form of visible light. The study of how this energy affects our environment falls within the purview of meteorology, a discipline that has experienced an independent development and that has sufficiently different problems from solar-terrestrial physics that it can be regarded as a separate but neighboring discipline. In …