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The constant A in the Richardson-Dushman...

The constant `A` in the Richardson-Dushman equation for tungsten is `60 xx 10^(4) A m^(-2)`. The work function of tungsten is `4.5 eV`. A tungsten cathode having a surface area `2.0 xx 10^(-5) m^2` is heated by a `24 W` electric heater. In steady state, the heat radiated by the cathode equals the energy input by the heater and the temperature becomes constant. Assuming that the cathode radiates like a blackbody, calculate the saturation current due to thermions. Take Stefan constant `= 6 xx 10^(-8) W m^(-2) K^(-4)`. Assume that the thermions take only a small fraction of the heat supplied.

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The constant A in the Richordson-Dushman equation is 60 xx 10^4 A m^(-2) K^(-2) for tungsten. A tungsten cathode has a total surface area of 2.0 xx 10^(-5) m^2 and operates at 2000 K . The work function of tungsten is 4.55 eV . Calculate the electric current due to thermionic emission.

The constant A in the Richordson-Dushman equation is 60 xx 10^4 A m^(-2) K^(-2) for tungsten. A tungsten cathode has a total surface area of 2.0 xx 10^(-5) m^2 and operates at 2000 K . The work function of tungsten is 4.55 eV . Calculate the electric current due to thermionic emission.

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