Of the total incident solar radiation the proportion of PAR is

Options

A. About 70%
B. Aboul60%
C. Less than 50%
D. More than 80%

Answer

To solve the question regarding the proportion of Photosynthetically Active Radiation (PAR) from the total incident solar radiation, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of PAR**:
- PAR stands for Photosynthetically Active Radiation. It refers to the portion of the light spectrum that plants can use for photosynthesis, specifically the wavelengths between 400 and 700 nanometers.

2. **Identify the Total Incident Solar Radiation (ISR)**:
- Total incident solar radiation is the total amount of solar energy that reaches the Earth's surface. It encompasses all wavelengths of light, not just those used in photosynthesis.

3. **Determine the Proportion of PAR**:
- Research and scientific consensus indicate that PAR typically constitutes a smaller fraction of the total incident solar radiation. Specifically, it is often reported that PAR accounts for less than 50% of the total ISR.

4. **Evaluate the Options Given**:
- The options provided are:
- About 70%
- About 60%
- Less than 50%
- More than 80%
- Based on the understanding that PAR is less than 50% of ISR, the correct answer is **"less than 50%"**.

5. **Conclude the Answer**:
- Therefore, the proportion of PAR from the total incident solar radiation is **less than 50%**.

### Final Answer:
The proportion of PAR from the total incident solar radiation is **less than 50%**.

---