    Question

# A gas absorbs a photon of $355\mathrm{nm}$ and emits it at two wavelengths. If one of the emissions is at $680\mathrm{nm}$, the other is at

A

$1035\mathrm{nm}$

No worries! We‘ve got your back. Try BYJU‘S free classes today!
B

$325\mathrm{nm}$

No worries! We‘ve got your back. Try BYJU‘S free classes today!
C

$743\mathrm{nm}$

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
D

$518\mathrm{nm}$

No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

## The correct option is C $743\mathrm{nm}$Step 1: Given dataThe wavelength of the photon$=355\mathrm{nm}$The wavelength of one emission$=680\mathrm{nm}$Step 2: Calculating the other wavelengthAccording to the formula, Absorbed energy$=$emitted energy$⇒\frac{\mathrm{hc}}{\mathrm{\lambda }}=\frac{\mathrm{hc}}{{\mathrm{\lambda }}_{1}}+\frac{\mathrm{hc}}{{\mathrm{\lambda }}_{2}}$$⇒\frac{1}{\mathrm{\lambda }}=\frac{1}{{\mathrm{\lambda }}_{1}}+\frac{1}{{\mathrm{\lambda }}_{2}}$$⇒\frac{1}{355}=\frac{1}{680}+\frac{1}{{\mathrm{\lambda }}_{2}}$$⇒\frac{1}{{\mathrm{\lambda }}_{2}}=\frac{1}{355}-\frac{1}{680}$$⇒\frac{1}{{\mathrm{\lambda }}_{2}}=\frac{680-355}{355×680}$$⇒{\mathrm{\lambda }}_{2}=743\mathrm{nm}$Final answer: The other wavelength that photon emits$=743\mathrm{nm}$  Suggest Corrections  0      Explore more