Ultraviolet radiation

Definition

Ultraviolet radiation is a type of electromagnetic radiation with wavelengths shorter than visible light but longer than X-rays, ranging from about 10 nm to 400 nm. It has higher energy than visible light and can cause chemical reactions and ionization.

5 Must Know Facts For Your Next Test

1. Ultraviolet radiation is divided into three types: UVA, UVB, and UVC based on wavelength.
2. It plays a crucial role in vitamin D synthesis in the skin but can also cause damage like sunburn and increase the risk of skin cancer.
3. The Earth's atmosphere absorbs most UVC and some UVB radiation, while UVA largely reaches the surface.
4. UV radiation can ionize atoms and molecules, leading to the formation of ozone in the stratosphere which protects life from harmful UV exposure.
5. Spectroscopy using UV light is a common method to study electronic transitions in atoms and molecules.

Review Questions

• What are the three types of ultraviolet radiation based on wavelength?
• How does ultraviolet radiation contribute to both health benefits and risks?
• Why does most UVC radiation not reach the Earth's surface?

Related terms

Electromagnetic Spectrum: The range of all types of electromagnetic radiation, including gamma rays, X-rays, ultraviolet light, visible light, infrared light, microwaves, and radio waves.

Photon: A quantum of electromagnetic energy that exhibits both wave-like and particle-like properties.

Ozone Layer: A region of Earth's stratosphere that contains a high concentration of ozone (O_3) molecules; it absorbs most of the Sun's harmful ultraviolet radiation.