The work functions of cesium (Cs) and lithium (Li) metals are 1.9 eV and 2.5 eV , respectively. If we incident a light o…
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The work functions of cesium (Cs) and lithium (Li) metals are 1.9 eV and 2.5 eV , respectively. If we incident a light of wavelength 550 nm on these two metal surfaces, then photo-electric effect is possible for the case of [JEE Main 2025, 22 Jan (Shift 1)]
✓ Correct answer: d) Cs only
ExplanationCesium (Cs): Work function = 1.9 eV Since 2.26 eV (incident photon energy) > 1.9 eV , photoelectric emission is possible.Lithium (Li): Work function = 2.5 eV Since 2.26 eV (incident photon energy) < 2.5 eV, photoelectric emission is not possible.
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