Question

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

• A. $1035nm$
• B. $325nm$
• C. $743nm$
• D. $518nm$

Answer 1

Answer: (C)

$743nm$

The energy of absorbed photon $=$ Sum of the energies of emitted photons

$\frac{hc}{355\times {10}^{-9}}=\frac{hc}{680\times {10}^{-9}}+\frac{hc}{x}$

$x=742.77\times {10}^{-9}m$

i.e., $743nm$.