Medically most impoant form of UV radiation is –
**Core Concept**
Ultraviolet (UV) radiation from the sun is classified into three main categories based on wavelength: UVA, UVB, and UVC. UVA radiation has the longest wavelength, while UVC has the shortest wavelength.
**Why the Correct Answer is Right**
UVB radiation is medically the most important form of UV radiation as it is primarily responsible for causing sunburn and plays a crucial role in the development of skin cancer, including melanoma. This is because UVB radiation has sufficient energy to cause DNA damage, leading to mutations in skin cells. The enzyme cyclobutane pyrimidine dimer (CPD) is involved in the formation of dimers due to UVB-induced DNA damage.
**Why Each Wrong Option is Incorrect**
**Option A:** UVA radiation is also a form of UV radiation, but it is less energetic than UVB and primarily causes photoaging and wrinkling of the skin.
**Option B:** UVC radiation is the most energetic form of UV radiation, but it is almost completely absorbed by the Earth's atmosphere and does not pose a significant risk to human health.
**Option C:** There is no other medically significant form of UV radiation besides UVA, UVB, and UVC.
**Clinical Pearl / High-Yield Fact**
It's essential to note that UVB radiation is most intense between 10 am and 4 pm, and its intensity increases with altitude and proximity to the equator. This highlights the importance of sun protection measures, such as seeking shade, wearing protective clothing, and applying sunscreen with a Sun Protection Factor (SPF) of at least 30.
**Correct Answer: D. UVB radiation**