Radiation and Absorption of Energy by Tungsten Filaments at Low Temperatures

The radiation of energy from a thoriated tungsten filament and the absorption of the energy radiated from the surrounding bulb have been measured by a method which eliminates difficulties arising from cooling effects of the leads. For a filament at a uniform temperature TF in a bulb at temperature TB the net radiation W in watts cm−2 is the difference between the outgoing radiation WR and the absorbed radiation WA. For values of TF from 225° to 580°K and TB from 77° to 473°K logWR=83.7105−100+5.332logTF,logWA=83.7105−100+4.462logTB+0.87logTF.The resistivity R0 in this same range is given by logR0=91.7123−100+1.23logTF.The characteristics, current, voltage, resistance, and energy radiated as functions of temperature are tabulated.