a photon of 3000 Angstrom is absorbed by a gas and then re-elected as two photons. One photon is red 7600  Angstrom  .  What wavelength of other photon? 

Here I am knowing solution but I am not able to understand that why we are using formula ( h*c/lambda of total =  h*c/lambda of 1 +h*c / lambda of 2 )

Please solve it 

Asked by rajarage18 | 23rd Jan, 2020, 08:00: PM

Expert Answer:

E =hc/λ

Wavelength of 1st photon = λ1

Wavelength of 2nd photon = λ2

Energy conservation-

E(Total) = E1 + E2 = Emitted energy

hc/ λ  = hc/ λ + hc/ λ2 

1/3000 = 1/7600 + 1/ λ2

1/ λ2  = (1/3000 – 1/7600)

 λ2   = 4960 Angstrom = wavelength of second photon

Answered by Ravi | 24th Jan, 2020, 10:05: AM