. The Complete Photo-Electric Emission from the Alloy of Sodium and Potassium. ciently high voltage was maintained between thealloy and radiator, is illustrated by fig. 5, which is plotted from actualmeasurements. The ordinates represent the currents in arbitrary units, andthe abscissae approximate temperatures. The applied potential was 100 volts. It will be seen that the current increases rapidly with the temperature upto a certain point, beyond which it rises less and less rapidly, and ultimatelybecomes stationary. This phenomenon is already well known, and is explainedby the fact that at t
. The Complete Photo-Electric Emission from the Alloy of Sodium and Potassium. ciently high voltage was maintained between thealloy and radiator, is illustrated by fig. 5, which is plotted from actualmeasurements. The ordinates represent the currents in arbitrary units, andthe abscissae approximate temperatures. The applied potential was 100 volts. It will be seen that the current increases rapidly with the temperature upto a certain point, beyond which it rises less and less rapidly, and ultimatelybecomes stationary. This phenomenon is already well known, and is explainedby the fact that at the higher temperatures the emission is very large andthe applied potential is not sufficiently high for saturation, owing to themutual repulsion of the emitted electrons. This kind of effect was firstobserved by J. E. Lilienfeld,* who accounted for it along lines similar to •^ Phys. Zeitschrift, vol. 9, p. 193 (1908). 364 Dr. W. Wilson. The Complete Photo-electric the above. It has also been considered by C. D. Child,* and at greaterlength, more recently, by I. TEMPERATURE (C.) sSo Fig. 5. In fig. 6 is shown the dependence of the current on the applied potentialwhen the radiator temperature was 573° C. The abscissae will represent voltswhen multiplied by 146. The current, as will be seen from the figure, ispractically saturated with 200 volts. In the actual measurements describedbelow, the applied potential was 350 volts, so that the currents obtainedwdth the temperature stated above, and with all lower temperatures, wereundoubtedly saturated. Higher radiator temperatures were employed, butthe saturation of the currents was less satisfactory. The saturation curve corresponding to a radiator temperature of 624^ C. isshown in fig. 7. In this case saturation appears to be just reached at thehighest potential at my disposal, namely, 350 volts. (The abscissae in fig. 7have to be multiplied by 1*46 to give volts.) It is possible that the * Phys. Eev., vol. 32,
Size: 1381px × 1809px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookaut, bookcentury1900, bookdecade1910, bookidphiltrans09016394
