Physics 125 - General Physics II - Spring 2008
Online resources
Here is a short list of useful links to some learning resources for this course:
Wilson/Buffa
Companion website:
http://www.aw-bc.com/wilson/ may have some useful practice
material, but I don't use it much.
(Select one of the texts, the current one
or the black
one, then use the “Jump to” drop-down menu to choose a chapter.)
We will be getting into some material in Ch. 20 that requires a knowledge of waves, you may want to browse through some of these simulations: they show animation of various concepts from waves and sound. In addition, you should study Chapters 13 and 14 in the text to be sure you know the basics of waves (especially if you are a transfer student).
Reflection of waves on a string, with fixed or free boundaries.
Superposition of waves for several cases.
Fourier synthesizer with sound.
For more simulations that I used last semester, see the Physics 124 resources web page.
Some examples of scalar and vector fields (to motivate electric field in Ch. 15):
Temperature - a scalar field indicated by colors - notice also that the boundaries between colored regions are constant temperature contours
Streamlines of wind - this is one way to represent a vector field - the wind would carry a balloon along a streamline in the direction of the wind velocity
Wind plot - an example of a vector field indicated by flags, motivated by the use of flags placed up in the wind to indicate which way it is blowing
Physlets for electrostatics:
Third-law force pair between charges - Coulomb's Law
Distance dependence of Coulomb's Law
Electric field and field lines with movable test charge
A test charge in a uniform field (and "not a test charge")
Analogy with gravity (point charges)
Electric Field of a point charge
Electric Field of two like charges
Motion of a test charge (not necessarily along the field lines!)
Field of two charges (various combinations)
Equipotentials of various charge combinations
Physlets for DC circuits:
Conventional vs. actual current
Physlets for magnetism:
Electric charge in a magnetic field
Magnetic field from a long straight wire
Magnetic field from two wires, with unequal currents, field vectors, and compass!
Magnetic field from one or two loops of wire
Magnetic field from numerous loops of wire
Magnetic field inside a coaxial cable
Rotation of current-carrying loop (starts discussion of motors)
Physlets for electromagnetic waves:
Moving charge, user controlled
Electric fields due to a moving point charge
Slow-motion simulation of an electromagnetic wave
Physlets for Ch. 22 and 23: Geometrical Optics:
Animated gif: illustration of traveling pulse and reflection at boundaries
Reflection and refraction of waves (by Huygen's principle, which we haven't covered, but I'll do this in class)
Reflection and Refraction - showing wavelets from Huygen's principle
Fermat principle is another way to choose where the reflected and/or refracted rays go
World as seen by a fish from underwater!
Reflection/refraction of a flashlight beam from underwater - motivates total internal reflection
Total internal reflection in an optic fiber
Simulation of light paths through a prism (don't need to download Chinese characters if it asks) - drag the corners of the prism to create an arbitrary triangular prism, see lots of reflected rays.
Pentaprism - also include a stereo (3d) feature, press s and defocus your eyes to see the 3d image in the middle of the screen
Virtual Optical Bench - requires some practice (and there is a full-screen version)
The Human Eye - simulates the normal and near- or farsighted eye, and how a corrective lens helps to form an image on the retina
Physlets for Ch. 24: Physical Optics
Another example of Interference between waves from two point sources
Ripple tank simulation (you can add a second source to see interference)
Ripple tank simulation (add your own sources and move them around)
Thin Film - showing transmitted and reflected wave
Thin film interference with white light - simulates soap film colors, but there is quite a bit of extra detail in the text (link unavailable).
To discuss polarization by absorption, recall that EM waves are transverse, as seen in the slow-motion simulation, and the polarization direction is along the E vector. This polarization can be along one axis, say the x axis if the wave travels along z, or along a perpendicular direction like the y axis, or along some other arbitrary direction (but still transverse) as shown in this simulation of several states of polarization (link unavailable). After seeing these simulations, it should be easier to understand the demonstration that used three linear polarizers (over the overhead projector) to illustrate Malus' Law.
We also want to understand polarization by reflection. Review the interaction of the wavefronts with the surface during reflection by looking at the simulation of Huygen's principle and its application to reflection. Then recall that radiation of a dipole is suppressed in the direction of the dipole, as seen when you choose the SHO option from the drop-down menu in the Retarded fields physlet. Now review the material in your text, on pp. 800-802, especially Fig. 24-23.
I also mentioned optical rotatory effects, which is explained in a very simple way by this physlet on Twisting Light.
Physlets for Ch. 27 and 28: Atomic Structure and Quantum Mechanics
A Blackbody Spectrum simulation shows how the color changes as an object is heated to very high temperatures. (link unavailable)
Recall that strings confined to a length can vibrate as standing waves. A membrane like a drum head can also vibrate as a standing wave. These vibrations have particular frequencies and shapes, and are somewhat analogous to the standing wave of the electron (wavefunction) as it is confined around a nucleus by the electric force of the nucleus. The electron wavefunctions around a nucleus are called orbitals, and are shown in just about every chemistry book. Web sites are available to explore atomic orbitals. There is a site that let you rotate a d-orbital to help visualize it. Similar orbitals are responsible for bonding in molecules, like the hydrogen molecule. In some structured materials and semiconductor devices, the electron wavefunctions look more like the standing waves of a rectangular membrane.
Ch. 29: Nuclear Structure
I have prepared some PowerPoint presentations which have links to web sites with nuclear data, etc. If the links do not work from within the PowerPoint presentation, use these links:
Part 1: Biographical sketch of Becquerel
Part 2: X-ray Form Factors, Attenuation Lengths, etc.
Part 3: Korean database with nuclear levels for Co-60 Lund database of nuclear isotope data indexed through a periodic table
Part 4: Berkeley Table of Isotopes Brookhaven NUDAT charts
IAEA Nuclear Safety homepage nuclide chart with Java controls (France) Nuclear wallet cards
Some more resources for radiation safety:
CDC radiation emergencies – isotopes, see: http://www.bt.cdc.gov/radiation/isotopes/index.asp
CDC radiation emergencies http://www.bt.cdc.gov/radiation/index.asp
EPA radiation information http://www.epa.gov/radiation/
EPA link to fact sheets http://www.epa.gov/radiation/radionuclides/index.html
