WebElements Periodic Table of the Elements Electricity & Magnetism - Download free content from MIT Chapter 3 Classical physics could not explain the spectra of black bodies. It predicted that the intensity (power emitted at a given wavelength) of emitted light should increase rapidly with decreasing wavelength without limit (the "ultraviolet catastrophe"). In the figure below, the curve labeled "Rayleigh-Jeans law" shows the classically expected behavior. However, the measured spectra actually showed an intensity maximum at a particular wavelength, while the intensity decreased at wavelengths both above and below the maximum. E = hf (Planck's formula) where h (Planck's constant) is an exceedingly small number whose value we do not need here, and f is the frequency of vibration of the oscillator (the number of times it vibrates per second). Also in the late 1800s, experimental physicists were measuring the emission of electrons from metallic objects when they shined light on the object. 3.2. Line spectra are another example of phenomena that could not be explained by classical physics. l=h/p
How Time Dilation Makes Sense previous home next PDF Michael Fowler, UVa Physics, 12/1/07 “Moving Clocks Run Slow” plus “Moving Clocks Lose Synchronization” plus “Length Contraction” leads to consistency! The object of this exercise is to show explicitly how it is possible for two observers in inertial frames moving relative to each other at a relativistic speed to each see the other’s clocks as running slow and as being unsynchronized, and yet if they both look at the same clock at the same time from the same place (which may be far from the clock), they will agree on what time it shows! Suppose that in Jack’s frame we have two synchronized clocks C1 and C2 set 18 x 108 meters apart (that’s about a million miles, or 6 light-seconds). Jill’s spaceship, carrying a clock C', is traveling at 0.6c, that is 1.8 x 108 meters per second, parallel to the line C1C2, passing close by each clock. Suppose C' is synchronized with C1 as they pass, so both read zero. What does clock C' (the clock on the ship) read as it passes C2?
altvw96 "The Alternate View" columns of John G. Cramer by John G. Cramer At the end of 1998 my wife, daughter, and I attended the Renaissance Weekend at Hilton Head Island, South Carolina. Programming at the Renaissance Weekend is rather like that of an up-scale science fiction convention, except that the panels have far more participants than SF Con panels, with each panelist allowed only a 5-minute "sound bite" to describe his or her take on the subject under discussion. An investment banker told me later that he was surprised to learn that science had so many unsolved problems. So here's my list of the top seven unsolved problems in physics and astrophysics. . This new understanding raises far more questions then it answers. The standard model of particle physics, which is called quantum chromodynamics or QCD, is in many ways an excellent theory. A new higher energy particle accelerator, the large hadronic collider or LHC, will begin operation at the CERN laboratory in Geneva around 2005. .