life of pi summary

1. Experiments show that if a discharge tube is exhausted to a low pressure (0.01 mm of Hg), cathode rays are produced.2. Cathode rays are fast moving electrons having a negative charge. They contain the smallest quantity of electricity from nature i.e., 1.602 x 10'19 coulombs.An electron has a mass 9.1 x 10~31 kg and hence is about —— limes lighter 1840than the hydrogen atom.3. Prof. J.J. Thomson proposed the hypothesis that cathode rays were streams ofnegatively charged particles. He was the pioneer who devised an experiment £by which the specific charge — of such particles was determined. m4. Milikan's oil drop experiment was the first direct experimental proof of the atomic nature of electric charge.5. The photoelectric effect is a process whereby electrons can be ejected from a metallic surface when light is incident on that surface. Einstein provided a successful explanation of this effect by extending Planck's quantum hypothesis to the electromagnetic field, in this model, light is viewed as a stream of particles called photons, each with energy E = hv, where v is the frequency and h is Planck's constant The kinetic energy of the ejected photoelectron is given by (hv - wj, where wo is the work function of the metal.6. X-rays from an incident beam are scattered at various angles by elections in a target such as carbon. In such a scattering event, a shift in wavelength is observed for the scattered X-rays, and the phenomenon is known cs the Compton effect. Classical physics does not explain this effect. If the X-rays is treated as a photonconservation of energy and momentum applied to die photon-election collisions yields the following expression for the Comptonshift:-(1-cos a), mcwhere m is the mass of the electron, c is the speed of light and a is the scattering angle.7. All matter exhibits both particle and wave character. The dualistic nature of matter was proposed by de-Broglie. The de-Broglie wavelength of any particle of mass m and velocity v is given by x = t.-±. p mv£and the frequency of matter waves obeys the Einstein relation i) = —, where hE is the total energy of the particle. Subsequent experiments that confirmed the concept of matter waves included the observation of electron diffraction by Davisson and Germer and independently by Thomson.8. The wavelengths of visible objects are far too small for their wavelike nature to be apparent in everyday life. The wavelike nature of electrons becomes visible when they are reflected from single crystals or diffracted by ultra-thin materials.