Compare the emissivities of a caesium-coated tungsten cathode at 1000 K and that of a pure tungsten cathode at 2700 K. Assume the constant B in the Richardson-Dushmann equation to be the same for both cathodes.

Compare the emissivities of a caesium-coated tungsten cathode at 1000

1.	Compare the emissivities of a caesium-coated tungsten cathode at 1000 K and that of a pure tungsten cathode at 2700 K. Assume the constant B in the Richardson-Dushmann equation to be the same for both cathodes.
Answer» Solution :The RATIO of the saturation currents of the two cathodes is `x=(i_(1))/(i_(2))=((T_(1))/(T_(2)))^(2)EXP((A_(2))/(kT_(2))-(A_(1))/(kT_(1)))`

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Compare the emissivities of a caesium-coated tungsten cathode at 1000 K and that of a pure tungsten cathode at 2700 K. Assume the constant B in the Richardson-Dushmann equation to be the same for both cathodes.

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