Which range of wavelenght (in nm) is called photosyntehtically active radiation (PAR)?

Options

A. 100-390
B. 390-430
C. 400-700
D. 760-100,00

Answer

To determine the range of wavelengths known as photosynthetically active radiation (PAR), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of PAR**:
- Photosynthetically Active Radiation (PAR) refers to the portion of the light spectrum that plants use for photosynthesis.

2. **Identify the Wavelength Range of Solar Radiation**:
- Solar radiation reaching the Earth spans a wide range of wavelengths, typically from about 300 nm (ultraviolet) to 2600 nm (infrared).

3. **Narrow Down the Relevant Wavelengths**:
- Among the total solar radiation, only a specific range is utilized by plants for photosynthesis. This range is crucial for the process of converting light energy into chemical energy.

4. **Determine the Specific Range for PAR**:
- Research and scientific consensus indicate that the wavelengths used in photosynthesis fall between 400 nm and 700 nm.

5. **Select the Correct Option**:
- Based on the provided options:
- Option 1: 100 to 390 nm
- Option 2: 390 to 430 nm
- Option 3: 400 to 700 nm
- Option 4: 760 to 10,000 nm
- The correct answer is **Option 3: 400 to 700 nm**.

### Final Answer:
The range of wavelengths called photosynthetically active radiation (PAR) is **400 to 700 nm**.

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