Here’s a explanation:
Quantum yield tells us how efficiently light causes a chemical reaction.
- If every photon makes one molecule react, quantum yield = 1.
- If some photons don’t cause a reaction, quantum yield < 1.
- If one photon causes more than one reaction, quantum yield > 1.
Example:
- 100 photons absorbed, 80 molecules react → quantum yield = 0.8 (80% efficient).
In short: Quantum yield = how many molecules react per photon absorbed.