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

Options

A. 100-390
B. 390-430
C. 400-700
D. 760-10,000

Explanation

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 Wavelength**:
- Wavelength is the distance between successive peaks of a wave, commonly measured in nanometers (nm) for light.

2. **Identify the Importance of Wavelength in Photosynthesis**:
- Photosynthesis is the process by which plants convert light energy into chemical energy. The efficiency of this process depends on the wavelengths of light absorbed by chlorophyll and other pigments.

3. **Define Photosynthetically Active Radiation (PAR)**:
- PAR refers to the range of light wavelengths that plants use for photosynthesis. This range is crucial for the growth and energy production in plants.

4. **Determine the Specific Range of PAR**:
- The range of wavelengths that is optimal for photosynthesis is between 400 nm and 700 nm. This range includes the visible light spectrum, which is essential for the photosynthetic process.

5. **Select the Correct Option**:
- From the given options (100 to 390 nm, 390 to 430 nm, 400 to 700 nm, 760 to 10,000 nm), the correct range that corresponds to PAR is **400 to 700 nm**.

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

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