MEDIUMMCQ SINGLEJEE Mains ChemistryPhysical ChemistryAtomic StructureIntro
Ultraviolet light of 6.2 eV falls on an aluminium surface (work function = 4.2 eV). The kinetic energy (in joule) of the fastest electron emitted is approximately:
0.3 × 10⁻²¹ J
1.3 × 10⁻¹⁹ J
2.3 × 10⁻¹⁷ J
3.3 × 10⁻¹⁵ J
Explanation
KE = hν − W = 6.2 − 4.2 = 2 eV = 2 × 1.6 × 10⁻¹⁹ J = 3.2 × 10⁻¹⁹ ≈ 3 × 10⁻¹⁹ J
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