Electrical discharge tube

Fig. 14-4. An electric discharge tube, very low pressure. Electrons travel from the negative electrode to the positive electrode some of them pass through the triangular hole to produce a triangular spot on the fluorescent screen.

Fig. 14-5. An electric discharge tube with deflection electrodes.

This reaction has been postulated to explain emission from seeded flames and may also be important when sodium is added to hydrogen atoms pumped from an electric discharge tube. The emission from metal additives in flames has been studied particularly by Padley and Sugden169 170 and reviewed by Sugden171. Excitation of sodium in dilute H2+02 + N2 flames at atmospheric pressure is apparently due both to H+H+Na and H+OH+Na. 

Mercury is directly below cadmium in the periodic table, but has a considerably more varied and interesting chemistry than cadmium or zinc. Elemental mercury is the only metal that is a liquid at room temperature, and its relatively high vapor pressure contributes to its toxicological hazard. Mercury metal is used in electric discharge tubes (mercury lamps), gauges, pressure-sensing devices, vacuum pumps, valves, and seals. It was formerly widely used as a cathode in the chlor-alkali process for the manufacture of NaOH and Cl2, a process that has been largely discontinued, in part because of the mercury pollution that resulted from it. 

Fluorescent lights are electrical discharge tubes partially filled by Ne (red emission), Ar (blue emission), or K, Hg (blue-green), or Na vapor, or other material, which fluoresce when electrical current is sent thought the tube the characteristic narrow-band fluorescent emission forces a coating of CaWC>3 or ZnO or other "phosphors" on the inside of the tube to fluoresce as "white light."... 

Neon is primarily used in luminous tubes (vacuum electric discharge tubes), airplane beacons, helium-neon lasers, high-voltage indicators, cryogenic refrigerant, and laboratory experiments. 

Helium is used along with oxygen by divers. Neon is used in neon sign electrical discharge tubes. Argon, krypton and xenon, are used in incandescent lamps. Radon a radioactive noble gas is used in the treatment of malignant growths. 

VC 6.2 One way to see the emission spectrum of hydrogen is to view the hydrogen in an electric discharge tube through a spectroscope, a device that separates the wavelengths. Why... 

---