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प्रश्न
Would you prefer a material with a high work-function or a low work-function to be used as a cathode in a diode?
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उत्तर
We will prefer a material with low work-function to be used as a cathode in a diode, so that electron emission can occur using a small amount of energy.
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संबंधित प्रश्न
Find the maximum frequency of X-rays produced by 30 kV electrons.
The work function of caesium metal is 2.14 eV. When light of frequency 6 × 1014 Hz is incident on the metal surface, photoemission of electrons occurs. What is the
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- maximum speed of the emitted photoelectrons?
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The constant A in the Richardson−Dushman equation for tungsten is 60 × 104 A m−2K−2. The work function of tungsten is 4.5 eV. A tungsten cathode with a surface area 2.0 × 10−5 m2 is heated by a 24 W electric heater. In steady state, the heat radiated by the heater and 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's Constant = 6 × 10−8 W m−2 K−1. Assume that the thermions take only a small fraction of the heat supplied.
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Answer the following question.
Define the term "Threshold frequency", in the context of photoelectric emission.
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- visible light.
Name the factors on which photoelectric emission from a surface depends.
