BLACK LIGHT (UV LIGHT)

Ultraviolet (UV) light is a type of electromagnetic radiation that lies just beyond the violet end of the visible light spectrum. It has shorter wavelengths and higher energy than visible light, but longer wavelengths than X-rays.

Key Points:

• Wavelength range: About 10 to 400 nanometers (nm)

• Invisible to humans: Our eyes cannot see UV light

• Source: The main natural source is the Sun

Types of Ultraviolet Light:

1. UVA (315–400 nm)

   • Least harmful

   • Causes skin aging and tanning

2. UVB (280–315 nm)

   • More energetic

   • Causes sunburn and can damage DNA

3. UVC (100–280 nm)

   • Most dangerous

   • Usually absorbed by Earth’s atmosphere

Uses:

• Sterilization (kills bacteria and viruses)

• Medical treatments (like skin conditions)

• Forensic analysis (detecting substances)

• Tanning lamps