Assertion: cathode's electron | /r/HasProperty | produced
Facets:
value: by heating the filament
type: MANNER
Source sentences:
text: The electrons are produced by heating the filament (Joule heating effect) i.e. a coil of wire made from tungsten, placed within a cup-shaped structure, a highly polished nickel focusing cup, providing electrostatic focusing of the beam on the anode.