NTA Abhyas JEE Main2020PhysicsDual Nature of MatterPractice
A photon of energy 10.2 eV corresponds to light of wavelength λ 0 . Due to an electron transition from n = 2 to n = 1 in a hydrogen atom, the light of wavelength λ is emitted. If we take into account the recoil of the atom when the photon is emitted, then
Options
- Aλ < λ 0
- Bλ > λ 0
- Cλ = λ 0
- DNone of these
Correct answer
B. λ > λ 0
Step-by-step solution
Without recoil of the atom, the entire energy is carried away by the photon. h c λ 0 = 10. 2   eV With recoil of the atom, energy is shared between photon and atom. So, the energy of the photon is less, hence its wavelength is more. h c λ < h c λ 0 ∴ λ 0 < λ