Question

In stratosphere most of the ozone formation is assisted by :

• A. \(\gamma\)-rays.
• B. visible radiations.
• C. ultraviolet radiation.
• D. cosmic rays.

Hint:

Remember the dual role of the ozone layer: it is formed by UV radiation, and it also protects life on Earth by absorbing most of the harmful incoming UV-B and UV-C radiation. This absorption is what leads to the destruction of ozone, creating a natural dynamic balance.

Answer 1

The Correct Option is C

The formation of ozone in the stratosphere is primarily facilitated by ultraviolet radiation. Let's explore the process step-by-step to understand why this type of radiation is crucial:

1. Oxygen Molecule (O₂) Dissociation:
   • Ultraviolet (UV) radiation from the Sun strikes an oxygen molecule (O_{2}).
   • This energy from the UV rays breaks the oxygen molecule into two individual oxygen atoms (O).
   • The reaction can be represented as: O_{2} \xrightarrow{UV} 2O
2. Ozone Formation:
   • The free oxygen atoms are highly reactive and will quickly combine with other O_{2} molecules to form ozone (O_{3}).
   • The reaction can be represented as: O + O_{2} \rightarrow O_{3}
   • This process is part of the ozone-oxygen cycle, regulating ozone concentrations in the stratosphere.
3. Relevance of Other Radiations:
   • \(\gamma\)-rays: These are high-energy electromagnetic waves but do not play a significant role in the ozone formation process as they are mostly absorbed by other atmospheric layers.
   • Visible Radiations: These wavelengths do not have sufficient energy to dissociate oxygen molecules to lead to ozone formation.
   • Cosmic Rays: These high-energy particles from outer space are not involved in the ozone formation process in the stratosphere.

Thus, the correct answer is that most ozone formation in the stratosphere is assisted by ultraviolet radiation. This energy allows the initiation of reactions that lead to the creation of ozone, an essential component for absorbing harmful UV radiation from the Sun.