Which of the following colours of light work(s) best for photosynthesis ?

Options

A. Green
B. Yellow
C. Blue and red
D. violet and yellow

Answer

To determine which colors of light work best for photosynthesis, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Photosynthesis**: Photosynthesis is the process by which plants convert light energy into chemical energy, producing food (carbohydrates) from carbon dioxide and water.

2. **Identify Photosynthetic Pigments**: The primary pigment involved in photosynthesis is chlorophyll. This pigment is responsible for absorbing light energy.

3. **Determine Light Absorption**: Chlorophyll absorbs light most effectively in certain wavelengths. Specifically, it absorbs blue (around 430-450 nm) and red (around 640-680 nm) light.

4. **Evaluate Other Colors**:
- **Green Light**: Chlorophyll reflects green light, which is why plants appear green. Since it is not absorbed, green light is not effective for photosynthesis.
- **Yellow Light**: Similar to green, yellow light is not effectively absorbed by chlorophyll and thus does not contribute significantly to photosynthesis.
- **Violet Light**: Chlorophyll does absorb violet light, but it is not as effective as blue light.

5. **Rank the Effectiveness**: Based on absorption, blue light works best for photosynthesis, followed by red light. Violet light is also absorbed but is less effective than blue.

6. **Conclusion**: The colors of light that work best for photosynthesis are blue and red.

### Final Answer:
The colors of light that work best for photosynthesis are **blue and red**.

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