What is the quantum yield of photosynthesis

Options

A. `33 %`
B. `9 %`
C. `12 %`
D. `78 %`

Answer

### Step-by-Step Solution:

1. **Understanding Quantum Yield**: Quantum yield in photosynthesis refers to the efficiency with which light energy is converted into chemical energy. Specifically, it is defined as the number of oxygen molecules produced per quantum (or photon) of light absorbed.

2. **Photon Requirement**: It has been established that, on average, 8 photons are required to produce one molecule of oxygen during the process of photosynthesis.

3. **Calculating Quantum Yield**: To find the quantum yield, we can use the formula:
\[ \text{Quantum Yield} = \frac{\text{Number of O}_2 \text{ molecules produced}}{\text{Number of photons absorbed}} \]
In this case, for every 8 photons absorbed, 1 molecule of O₂ is produced. Thus:
\[ \text{Quantum Yield} = \frac{1 \text{ O}_2}{8 \text{ photons}} = 0.125 \]

4. **Converting to Percentage**: To express the quantum yield as a percentage, we multiply by 100:
\[ \text{Quantum Yield (in percent)} = 0.125 \times 100 = 12.5\% \]

5. **Choosing the Nearest Option**: Among the given options (33%, 9%, 12%, 78%), the nearest value to 12.5% is 12%. Therefore, the correct answer is 12%.

### Final Answer:
The quantum yield of photosynthesis is **12%**.

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