The UV (ultraviolet) refers to electromagnetic radiation with wavelengths from about 10 to 400 nanometers, shorter than visible light but longer than X-rays
. It is a component of sunlight, making up about 10% of the Sun's total electromagnetic output, and includes UVA, UVB, and UVC types, classified by wavelength and energy
. The UV Index is a scale that predicts the intensity of ultraviolet radiation from the sun at a given place and time, typically ranging from 1 to 11+; it serves as a daily forecast to inform people about the potential risk of UV exposure
. The higher the UV Index, the greater the risk of skin damage and sunburn, guiding protective measures such as sunscreen use, wearing protective clothing, and limiting sun exposure
. In summary:
- UV radiation is invisible electromagnetic radiation shorter than visible light (10–400 nm), including UVA, UVB, and UVC
- The UV Index is a forecast scale measuring the expected strength of UV radiation from the sun, helping people manage sun exposure risk
- Protective actions depend on the UV Index level, with higher values indicating greater need for sun protection
