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» <html><body><p><br/></p>Solution :The <a href="https://interviewquestions.tuteehub.com/tag/ratio-13379" style="font-weight:bold;" target="_blank" title="Click to know more about RATIO">RATIO</a> of the saturation currents of the two cathodes is <br/> `x=(i_(<a href="https://interviewquestions.tuteehub.com/tag/1-256655" style="font-weight:bold;" target="_blank" title="Click to know more about 1">1</a>))/(i_(<a href="https://interviewquestions.tuteehub.com/tag/2-283658" style="font-weight:bold;" target="_blank" title="Click to know more about 2">2</a>))=((T_(1))/(T_(2)))^(2)<a href="https://interviewquestions.tuteehub.com/tag/exp-979975" style="font-weight:bold;" target="_blank" title="Click to know more about EXP">EXP</a>((A_(2))/(kT_(2))-(A_(1))/(kT_(1)))`</body></html>

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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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