Properties of a cathode used in thermionic valves.

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  •  It should have a low work function. A low work function helps to emit electrons from the cathode surface in a comparatively lower temperature
  • It should have a high melting point. The temperature required to emit an electron from the cathode surface is quite high compared to the melting point of normal metals. A lower melting point causes vaporization of metals before they emit electrons.
  • It should have high mechanical strength.

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