Question

In which one of the following regions of the electromagnetic spectrum does the maximum atmospheric scattering occur?

• A. UV
• B. IR
• C. Radiowave
• D. Microwave

Hint:

The shorter the wavelength of the light, the greater the scattering effect. This is why UV light, with its short wavelengths, experiences the most scattering in the atmosphere.

Answer 1

The Correct Option is A

Atmospheric scattering is a process where particles or molecules in the atmosphere cause the light to deviate from its original path. The degree of scattering depends significantly on the wavelength of the incident light. The shorter the wavelength, the greater the scattering.
Step 1: Understanding Rayleigh Scattering
Rayleigh scattering is the dominant form of scattering for wavelengths much larger than the size of atmospheric molecules. It is inversely proportional to the fourth power of the wavelength (\( \lambda \)), meaning that shorter wavelengths scatter more efficiently. The equation for Rayleigh scattering is given by:
\[ I \propto \frac{1}{\lambda^4}, \] where \( I \) is the intensity of scattered light and \( \lambda \) is the wavelength. Step 2: Comparing the regions of the electromagnetic spectrum
- UV (Ultraviolet): The UV region has wavelengths ranging from about 10 nm to 400 nm. These wavelengths are shorter than visible light and are scattered much more effectively by atmospheric molecules.
- IR (Infrared): The infrared region has wavelengths ranging from 700 nm to 1 mm. Although it is longer than UV, it still experiences some scattering, but much less than UV.
- Radiowave: Radiowaves have wavelengths that range from 1 mm to 1000 km, and they are scattered very minimally compared to UV or IR.
- Microwave: Microwaves also have long wavelengths and experience very little scattering by the atmosphere.
Step 3: Conclusion
Due to the relationship between wavelength and scattering, UV light, with its shorter wavelengths, undergoes the maximum atmospheric scattering, which is why the correct answer is (A) UV. Thus, the correct answer is (A) UV.