Give one use of the UV ray

Explanation

**Step-by-Step Solution:**

1. **Understanding UV Rays**: Ultraviolet (UV) rays are a type of electromagnetic radiation that is invisible to the human eye. They have higher energy than visible light and can have both beneficial and harmful effects.

2. **Application of UV Rays**: One significant use of UV rays is in water purification. This application leverages the properties of UV rays to eliminate harmful microorganisms from water.

3. **Mechanism of Water Purification**: When UV rays are introduced into water, they penetrate the cells of bacteria and other pathogens. The energy from the UV rays disrupts the DNA of these microorganisms, rendering them unable to reproduce and effectively killing them.

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