What happens to absorbed UV radiation in the stratosphere?

• A. It is converted to heat following absorption by the ozone layer
• B. It is reflected back to space
• C. It passes through without interaction
• D. It is stored as chemical energy in ozone

Answer: (A)

UV radiation is absorbed by the ozone in the stratosphere, and that energy is converted into heat. When ozone molecules take in high‑energy UV photons, the energy goes into increasing the motion of surrounding gas molecules and driving chemical reactions, which warms the surrounding air. That warming is why the stratosphere is heated where ozone is present, rather than the UV being simply reflected or stored as chemical energy. Some scattering of light can occur, but the dominant outcome of UV absorption by ozone is heating the layer, helping protect life on Earth from the highest-energy UV radiation.