Physics 7C FAQ

• What topics are covered in this class?
  • waves, especially sound and light
  • interference
  • standing waves and musical instruments
  • optics and lenses
  • electric fields
  • magnetic fields
  • intro to quantum mechanics


• What math skills will I need?
  • using algebra to manipulate and solve an equation
  • graphing sine waves
  • how changing a function changes its graph
  • trigonometric functions
  • radian measure of angles
  • basic geometry, especially similar triangles and congruent angles
  • vector arithmetic
  • conceptual meaning of derivative and integral


• What materials should I have for this class?
  • Beyond the usual pencil and paper, you will definitely want graph paper and a straightedge. You will be doing a lot of graphing and you want it to be as precise as possible. If you don't think you'll be using a whole pack of graph paper, split one with some friends. Alternatively you can print out custom graph paper of whatever grid size you want at Incompetech.
  • A few different colors of pen/pencil (or a fancy click-pen with several colors) can be a very good way to write your notes in a more organized way, and to distinguish between several curves on the same graph.
  • Doing arithmetic in your head is impressive, but to speed things up you'll probably want a calculator. A scientific calculator will be enough for most purposes; if you want to do anything with graphing, matrices, statistics, programming, etc., I'd recommend a TI-82/83/84.
  • Your T.A. will occasionally give you stuff to take home and experiment with (light bulbs, lenses, magnets, etc.), so you might want a pouch or small box to keep those organized and make sure they don't get lost.


• What's the difference between a particle and a wave?
  • Both involve some sort of motion, but exactly WHAT is moving?
    • Particle motion means the OBJECT itself is moving forward.
    • Wave motion means that individual particles may be oscillating a little bit (usually forward/backward or up/down), but their oscillations all together form a DISTURBANCE that is propagating forward. That traveling disturbance also carries with it ENERGY and INFORMATION (such as wavelength, amplitude, period, etc.).


• What types of waves are there?
  • Transverse wave: the particles oscillate perpendicular to the direction of wave propagation. Imagine wiggling one end of a horizontal Slinky up and down.
  • Longitudinal wave: the particles oscillate parallel to the direction of wave propagation. Imagine wiggling one end of a horizontal Slinky forward and backward (along the length of the Slinky itself).
  • Torsional wave: the particles rotationally oscillate around the axis of wave propagation. Imagine repeatedly twisting one end of a horizontal Slinky clockwise and counterclockwise.
  • Pressure wave: alternating bands (or shells) of high pressure and low pressure spreading out through a gas or liquid. The usual example is sound waves in air or water. In this case we're not really treating it as particles whose location is being disturbed; what's being disturbed is the pressure itself (above and below standard atmospheric pressure).
  • Electromagnetic wave: also known as light (including visible light, ultraviolet, infrared, radio waves, microwaves, X-rays, etc.). What's oscillating here is not a physical object, but rather electric fields and magnetic fields. We'll look into this in more detail later in the quarter.



• This FAQ is a work in progress. If you have any questions that are not addressed here, please ask.
• Don't forget to check my general FAQ as well.