A gas absorbs a photon of 355 nm and emits at two wavelengths. If one of the emissions is at 680 nm , the other is at: - Chemistry MCQ FIITJEE AIEEE 2011 (Set Q) 2026 | ExamTest.live

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A gas absorbs a photon of 355 nm and emits at two wavelengths. If one of the emissions is at 680 nm, the other is at:

Solution & Step-by-step Explanation

By conservation of energy: E_{ab sor b e d} = E_{e mi tt e d 1} + E_{e mi tt e d 2} \frac{h c}{λ} = \frac{h c}{λ _{1}} + \frac{h c}{λ _{2}} ⟹ \frac{1}{λ} = \frac{1}{λ _{1}} + \frac{1}{λ _{2}} \frac{1}{355} = \frac{1}{680} + \frac{1}{λ _{2}} \frac{1}{λ _{2}} = \frac{1}{355} - \frac{1}{680} = \frac{680 - 355}{355 \times 680} = \frac{325}{241400} λ_{2} = \frac{241400}{325} \approx 742.7 nm .Rounding gives 743 nm .

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A gas absorbs a photon of 355 nm and emits at two wavelengths. If one of the emissions is at 680 nm, the other is at:

325 nm

743 nm

518 nm

1035 nm

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