UVB, or Ultraviolet B, is a type of ultraviolet radiation emitted by the sun. It has a shorter wavelength than UVA rays and is primarily responsible for causing sunburn and skin damage. UVB rays play a crucial role in the production of vitamin D in the skin, which is essential for bone health and immune function. Unlike UVA rays, which can penetrate deeper into the skin, UVB rays mainly affect the outer layer. This makes them a significant factor in the development of skin cancer, such as melanoma. To protect against UVB exposure, it is important to use sunscreen and wear protective clothing when spending time outdoors.