Question

Ozone protects Earth because:

• A. O(_3 leftrightarrow) O(_2) + O cycle absorbs UV
• B. Higher molecular weight
• C. Reflects sunlight
• D. Blocks IR rays

Hint:

The ozone layer is most effective at blocking UV-C and most of UV-B, which are the most biologically damaging wavelengths of ultraviolet light.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question asks for the mechanism by which the ozone layer filters out dangerous solar radiation.

Step 2: Detailed Explanation:
In the stratosphere, ozone ((O_3)) molecules undergo a continuous cycle called the Chapman cycle.
When (O_3) is hit by high-energy Ultraviolet (UV) radiation from the sun, it absorbs the energy and breaks apart into an oxygen molecule ((O_2)) and a free oxygen atom (O).
[ O_3 + text{UV photon} rightarrow O_2 + O ] These components then recombine to form ozone again, releasing heat. This cycle effectively converts harmful UV energy into thermal energy before it can reach the Earth's surface.

Step 3: Final Answer:
Ozone protects the Earth through the cyclic process of splitting and recombining, which absorbs harmful UV radiation.