IB Physics HL B.2.9 Greenhouse models Question Bank
Practise IB Physics HL B.2.9 by calculating molecular frequencies and constructing a resonance-based model of greenhouse warming.
- Syllabus
- First assessment 2025
- Course
- Physics HL
- Level
- HL
Practise IB Physics HL B.2.9 by calculating molecular frequencies and constructing a resonance-based model of greenhouse warming.
The diagram shows a simplified energy-balance model for the Earth surface-atmosphere system.

The following data are given:
Outline the physical mechanism by which some of the radiation emitted by the surface is absorbed by greenhouse gases in the atmosphere and re-radiated towards the surface.
<<Absorption by GHG molecules of>> radiation whose energy matches the energy difference between molecular levels
OR
<<Absorption of radiation that causes>> resonance of the GHG molecule
Followed by emission «from GHG molecules» in random/all directions
For MP2 do not accept towards the surface as that is in the stem of the
question.