UVB rays are a type of ultraviolet (UV) radiation from the sun that have shorter wavelengths and higher energy compared to UVA rays. They make up about 5% of the UV radiation reaching the Earth's surface but are very powerful and primarily affect the outer layers of the skin, known as the epidermis
. UVB rays are responsible for causing sunburn and can directly damage the DNA in skin cells, leading to mutations that increase the risk of skin cancers, including melanoma
. Unlike UVA rays, UVB rays do not penetrate deeply into the skin or through glass. They are most intense between 10 a.m. and 4 p.m., which is when sunburn risk is highest
. In addition to skin damage, UVB radiation can also harm the eyes by contributing to cataract formation
. Despite their harmful effects, UVB rays also play a beneficial role in stimulating vitamin D production in the skin
. In summary, UVB rays are high-energy ultraviolet rays from the sun that cause sunburn, contribute significantly to skin cancer risk, and affect mainly the skin's surface layers
