Light In Transparent Medium Research Articles

Determining the refractive index of transparent materials using total internal reflection in teaching experiment

In this paper, we introduce a three-dimensional demonstration for the refraction and reflection based on total internal reflection of light in transparent media, and discuss the reasons for the formation of circular bright areas and circular shadows, respectively. Then, according to the relationship between the diameter of circular shadows and bright areas, the depth of water, and the thickness of the polymethyl methacrylate plate, we described a teaching experiment based on total internal reflection of light to achieve refractive index measurement of transparent liquids and solids. The refractive index of transparent media measured using this method is in good agreement with reported data.

Limits on the Flux of Nuclearites and Other Heavy Compact Objects from the Pi of the Sky Project.

Many theories predict the existence of very heavy compact objects, that in terms of sizes would belong to the realms of nuclear or atomic physics, but in terms of masses could extend to the macroscopic world, reaching kilograms, tonnes, or more. If they exist, it is likely that they reach our planet with high speeds and cross the atmosphere. Because of their high mass-to-size ratio and huge energy, in many cases, they would leave behind a trail in the form of sound and seismic waves, etches, or light in transparent media. Here we show results of a search for such objects in visual photographs of the sky taken by the "Pi of the Sky" experiment, illustrated with the most stringent limits on the isotropic flux of incoming so-called nuclearites, spanning between 5.4×10^{-20} and 2.2×10^{-21} cm^{-2} s^{-1} sr^{-1} for masses between 100g and 100kg. In addition we establish a directional flux limit under an assumption of a static "sea" of nuclearites in the Galaxy, which spans between 1.5×10^{-18} and 2.1×10^{-19} cm^{-2} s^{-1} in the same mass range. The general nature of the limits presented should allow one to constrain many specific models predicting the existence of heavy compact objects and both particle physics and astrophysical processes leading to their creation, and their sources.

An inexpensive apparatus for the measurement of the group velocity of light in transparent media using a modified Helium–Neon laser

An apparatus is described for the measurement of the group velocity of light in transparent media. The apparatus uses a modified He–Ne laser as a stable, amplitude-modulated light source. With the aid of a single beam oscilloscope, results for the velocity of light in air accurate to ∼0.02% have been obtained. This accuracy is sufficient to enable the relationship between the group and phase velocities in transparent dispersive media to be experimentally verified.

An inexpensive apparatus for the measurement of the velocity of light in transparent media

An apparatus is described for the measurement of the velocity of light in air and transparent media. The apparatus uses solid-state light-emitting and detecting diodes, and can be constructed for about Pounds 25. With the aid of a single-beam oscilloscope and a two meter optical bench, results accurate to better than 1% can be obtained. This accuracy is shown to be sufficient for an experimental verification of the relationship between the group and phase velocities of light in a dispersive transparent medium.

The Scattering of X-Rays in Liquids

IN various notes published last year I dealt with the scattering of light in transparent media, and showed that its study initiated by the late Lord Rayleigh in his theory of the colour of the sky has other fascinating applications in the explanation of the colour of the sea and other transparent waters, and of the colour of ice on glaciers. The thermodynamic theory of “fluctuations” developed by Smoluchowski and Einstein formed the starting-point in the discussions, but I was careful to emphasise the important complications arising from the anisotrophy of the molecules in fluid media and showed how the necessary corrections in Einstein's theory may be made. A considerable measure of success was attained in attempting to correlate the behaviour of substances in the liquid and gaseous states in this respect, and in predicting the effects due to alterations of temperature and pressure. The study of the changes in the intensity and states of polarisation of the scattered light in passing from the liquid to the solid crystalline state and their explanation forms another important line of inquiry in which some progress has also been made.