Photosynthetically active radiation (PAR) represents the following range of wavelength

Options

A. 400-700 nm
B. 500-600 nm
C. 450-950 nm
D. 340-450 nm

Answer

To determine the range of wavelengths that represent Photosynthetically Active Radiation (PAR), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of PAR**:
- Photosynthetically Active Radiation (PAR) refers to the portion of the light spectrum that plants can use for photosynthesis. It is crucial for the growth and energy production in plants.

2. **Identify the Wavelength Range**:
- PAR is defined as the range of wavelengths from approximately 400 to 700 nanometers (nm). This range includes the visible light spectrum, which is essential for photosynthesis.

3. **Evaluate the Options**:
- Option 1: 400 to 700 nm - This is the correct range for PAR.
- Option 2: 500 to 600 nm - This range is too narrow and does not encompass the full spectrum of PAR.
- Option 3: 450 to 950 nm - This range exceeds the upper limit of PAR.
- Option 4: 340 to 450 nm - This range is too low and does not include the full spectrum of PAR.

4. **Conclusion**:
- Based on the definitions and evaluations, the correct answer is that Photosynthetically Active Radiation (PAR) represents the wavelength range of **400 to 700 nanometers**.

### Final Answer:
The correct range of wavelength for Photosynthetically Active Radiation (PAR) is **400 to 700 nanometers**.

---