Alisha Vira edited The_basic_apparatus_of_Franck__.tex  over 8 years ago

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The basic apparatus of Franck Hertz experiment is shown in Figure 1. Fig. \ref{fig:appartus}.  Argon tube and neon tube are used in this experiment. The tubes are highly evacuated and are filled with atoms. Within each tube, there is a filament, a control grid, an accelerating grid, a cathode and an anode. An accelerating voltage is applied between cathode and accelerating plate to provide electrons with kinetic energy. A retarding voltage is applied between anode and accelerating plate to attract more electrons to the anode. Control grid is necessary for argon and neon, but will be unnecessary for some atoms such as mercury. The function of the control grid is to attract more electrons from the filament. Electrons are emitted from the filament when the heating voltage is applied.