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Dual Nature of Radiation and Matter — Physics STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 SciencePhysicsDual Nature of Radiation and Matter1 Mark
MCQ
Find the wrong statement.
  • A
    An electron gun is to create electrons and then accelerate them to a very high speed.
  • B
    Thermionic emissions and photoelectric emissions are the same.
  • C
    The kinetic energy of photoelectrons vary.
  • D
    Vacuum tubes are thermionic devices.
✓

Answer

  1. Thermionic emissions and photoelectric emissions are the same.

Explanation:

No, thermionic emissions and photoelectric emissions are not the same. During thermionic emissions, the electrons are emitted from the metal surface by providing heat energy, whereas, during photoelectric emission light energy is emitted when electrons are emitted from the surface of the metal. So, it is the opposite in operation.

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