Emission and Absorption
Part of the Optics, Waves and Modern Physics section of Coddy's Physics journey. Lesson 41 of 53.
A drop between levels gives out one photon:
E photon = Eᵢ − E_f = hf = hc / λ
3 → 2: 1.89 eV, red light of about 658 nm. Only certain jumps: sharp colours.
Absorption: only a photon with exactly the energy of a jump lifts the electron.
Challenge
The electron in a hydrogen atom drops from n = 3 to n = 2. First find the energies of the two levels and the photon's energy, then its wavelength λ, in nm.
Try it yourself
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
All lessons in Optics, Waves and Modern Physics
1Reflection and Refraction
Reflection of LightThe Refractive IndexSnell's LawTotal Internal ReflectionDispersionApparent DepthRecap - Optical Fiber4Mechanical Waves
What a Wave IsTwo Graphs of a WaveWhen Pulses MeetInterferenceStanding WavesHarmonicsRecap - Guitar String