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Electron, Photon, Photoelectric Effect and X-Rays — Physics STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 SciencePhysicsElectron, Photon, Photoelectric Effect and X-Rays1 Mark
Question
The photoelectric threshold wavelength for potassium (work function being 2eV ) is (a) 310 nm(b) 620 nm(c) 1200 nm(d) 2100 nm
       
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Answer

(b) 620 nm

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