Question

Wave length of UV-A Rays:

• A. 50 nm – 100 nm
• B. 100 nm – 280 nm
• C. 280 nm – 320 nm
• D. 320 nm – 380 nm

Hint:

When considering sun protection, choose broad-spectrum sunscreens that cover both UV-A and UV-B rays to prevent skin damage.

Answer 1

The Correct Option is D

Understanding UV-A spectrum. UV-A rays have a wavelength range of 320 to 400 nm. These rays are part of the ultraviolet light spectrum that reaches the Earth from the sun. UV-A rays are known for their ability to penetrate deep into the skin, causing long-term skin damage such as premature aging and wrinkles. They can penetrate clouds and glass, making exposure possible even during cloudy weather or while indoors near windows.

Answer 2

To solve the problem, we need to identify the correct wavelength range for UV-A rays.

1. Understanding UV-A Rays:
UV-A rays are part of the ultraviolet (UV) radiation spectrum. The UV spectrum is divided into three main regions: UV-A, UV-B, and UV-C. UV-A rays have the longest wavelength among the UV rays, and their wavelength typically ranges from:

• UV-A: 320 nm to 380 nm
• UV-B: 280 nm to 320 nm
• UV-C: 100 nm to 280 nm

2. Analyzing the Options:
We are asked to select the wavelength range corresponding to UV-A rays. From the options, the correct wavelength range for UV-A rays is:

• Option (1) 50 nm - 100 nm is too short for UV-A rays and corresponds to UV-C.
• Option (2) 100 nm - 280 nm is the range for UV-C rays.
• Option (3) 280 nm - 320 nm is the range for UV-B rays.
• Option (4) 320 nm - 380 nm is the correct wavelength range for UV-A rays.

3. Conclusion:
The correct wavelength range for UV-A rays is 320 nm to 380 nm.

Final Answer:
The correct answer is (D) 320 nm - 380 nm.