What are the approximate peaks of light absorption of chlorophyll 'a'?

Options

A. 400 and 500 n,
B. 430 and 730 nm
C. 430 and 660 nm
D. 300 and 660 nm

Answer

To determine the approximate peaks of light absorption of chlorophyll 'a', we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the specific wavelengths at which chlorophyll 'a' absorbs light most effectively.

2. **Defining Action Spectrum**: The action spectrum is a graph that shows the rate of photosynthesis at different wavelengths of light. It helps identify the wavelengths that chlorophyll 'a' absorbs best.

3. **Identifying Key Wavelengths**: The action spectrum of chlorophyll 'a' typically shows peaks in the absorption of light. We need to identify these peaks.

4. **Analyzing the Graph**:
- The peaks of chlorophyll 'a' absorption occur around 430 nm and 660 nm.
- At approximately 400 nm, there is a peak, but it is not the highest.
- The absorption decreases after 660 nm and does not reach a peak at 730 nm.

5. **Evaluating Options**:
- Option 1 (400 and 500 nm) is incorrect because it does not include the significant peaks.
- Option 2 (430 and 730 nm) is incorrect because while 430 nm is correct, 730 nm is not a peak for chlorophyll 'a'.
- Option 3 (430 and 660 nm) is correct as both wavelengths are identified as peaks of absorption for chlorophyll 'a'.

6. **Conclusion**: The approximate peaks of light absorption of chlorophyll 'a' are at 430 nm and 660 nm.

### Final Answer:
The approximate peaks of light absorption of chlorophyll 'a' are at **430 nm and 660 nm**.

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