Gamma rays are electromagnetic radiations which we detect as quanta of energy or photons. When the radioactive source is confined so that it acts as a point source, the diminution in the number of photons incident on a given area is such...
Different colors of LED light illuminate a small corked test tube with no reaction. Ultraviolet light causes an explosion that shoots the cork across the room.
A pulse-modulated electromagnetic signal is simultaneously displayed in the time domain (on an oscilloscope) and in the frequency domain (on a spectrum analyzer). Using ∆n for the frequency spread (uncertainty in frequency) and ∆t for the...
The photoemission of electrons from a metal surface depends on the energy of the incident radiation and not on its intensity. Knowing the energy of the emitted photoelectrons and the frequency of the incident light, you can calculate a...
A direct observation that the photoelectric effect is color (i.e. frequency) dependent and not intensity dependent. We discharge an electroscope using UV radiation after all attempts to discharge it with light of a longer wavelength has...
Diffraction produces a bright spot where Poisson believed there would be darkness.
What It Shows
Edge diffraction around a 1/8" diameter steel ball bearing results in a visible spot in the center of its shadow. In 1818 this result—to the chagrin of Siméon D...
A point light source will produce seemingly sharp shadows which turn out to be not at all sharp when viewed under magnification. Narrow interference bands are seen within the shadow of a straight edge while more complicated shapes yield...
