Thermions are________________?
Correct answer: C. electrons
- A. protons
- B. positrons
- C. electrons
- D. photons
Explanation
Thermions are electrons emitted from a heated metal surface when thermal energy gives them enough energy to overcome the surface potential barrier. This process is called thermionic emission. The likely mistake is choosing photons because heating is involved, but photons are electromagnetic energy packets, not the emitted particles in thermionic emission.
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About Quantum Theory and Radiation
Quantum theory treats electromagnetic radiation as packets of energy called photons, with energy proportional to frequency through E equals hf. The topic covers Planck's hypothesis, photon momentum, the photoelectric effect, threshold frequency, work function and wave particle duality, distinguishing quantised energy exchange from classical continuous radiation.
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