Question

Photosynthetic Active Radiation (PAR) has the following range of wavelengths

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

Answer 1

The Correct Option is A

The question is asking about the range of wavelengths for Photosynthetically Active Radiation (PAR). This is a common concept in biology, particularly in the study of photosynthesis.

1. Understanding PAR: Photosynthetically Active Radiation (PAR) refers to the spectrum of light wavelengths that plants can use for photosynthesis. This covers the range of light that is effective for the photosynthetic process.
2. Wavelength Range: The wavelengths that constitute PAR are from 400 to 700 nanometers (nm). This range includes the violet to red light spectrum.
3. Eliminating Incorrect Options:
   • 450 - 950 nm: This range extends beyond visible light and includes infrared, which is not used for photosynthesis.
   • 340 - 450 nm: This range is too short and excludes much of the necessary red light used in photosynthesis.
   • 500 - 600 nm: This is only part of the visible spectrum, mainly the green light, and excludes the important blue and red wavelengths.
4. Correct Answer and Conclusion: The range of 400 to 700 nm covers the violet, blue, green, yellow, orange, and red light, making it the ideal and only correct range for PAR.

Therefore, the correct answer is the range 400 - 700 nm, as it encompasses all the wavelengths plants use during photosynthesis.