世纪之交的物理学(国外英语资料).docVIP

世纪之交的物理学(国外英语资料) The seventh chapter: physics at the turn of the century Objectives and requirements: Master of classical physics: at the beginning of twentieth Century on the two clouds; how roentgen discovered X - rays; natural radioactive discovery; electronics is found; familiar with: the crisis of classical theory at the beginning of twentieth Century. Teaching emphasis and difficulty: two dark clouds in classical physics at the beginning of the twentieth Century; how roentgen discovered X rays; the discovery of natural radial patterns; how electrons were discovered. . Faraday gained power for: drums, drums into the Faraday particle kinetic energy due to the collision of all transformed into heat, the kinetic energy by the thermometer temperature rise are measured, the value should be:. The ray is deflected in the magnetic field (radius R) in the following relation: obtained by the upper three formula:. Thus J.J. Thomson measured centimeter, electromagnetic unit / gram. The proof of the existence of electronic universal: J.J. Thomson using different materials as cathode, and different gas experiment results the charge mass ratio has the same magnitude, that under various conditions are the same negatively charged particle flow, has nothing to do with the electrode material, it has nothing to do with the gas components. Published in 1897 on cathode ray, the cathode ray has a much smaller load than the hydrogen ion, m/e.. The reason may be that M is small or E is large or has both. He knew from the Lenard experimental results, the cathode ray in the air through a distance of up to 1 cm, and the mean free path of air molecules only 10-5 cm, so the quality of cathode ray than air molecules are much smaller. The other experiment: 1) the photocurrent produced in the photoelectric effect In 1887, Hertz discovered the photoelectric effect, but the nature of the photocurrent produced was unclear. In 1899, J.J. Thomson measured the charge to mass ratio of the photocurren