Q. A gas absorbs photon of 355 nm and emits at two wavelengths. If one of the emission is at 680 nm, the other is at
A) 1035 nm
B) 325 nm
C) 743 nm
D) 518 bm
Explanation
(c)
Energy values are always additive.
$E_{total} = E_{1} + E_{2}$
$\frac{hc}{\lambda} = \frac{hc}{\lambda_{1}} + \frac{hc}{\lambda_{2}}$
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$\frac{1}{\lambda} = \frac{1}{\lambda_{1}} + \frac{1}{\lambda_{2}}$
$\frac{1}{355} = \frac{1}{680} + \frac{1}{\lambda_{2}}$
$\lambda_{2} = 742.77\ nm \approx 743\ nm$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.