Electromagnetic Spectrum and Atmospheric Windows MCQ with answer and solution

Concept

Reflection depends on surface roughness relative to wavelength, angle of incidence and wavelength of radiation.

Step-by-step solution

1. Standard texts list the factors that control reflected energy: surface roughness, angle of incidence, wavelength of radiation and the material of the surface. 2. Roughness, angle and wavelength are all in this list. 3. 'Type of electromagnetic radiation' is not listed as a separate factor. 4. So the answer is (D).

Explanation

How energy reflects from a surface depends on how rough the surface is compared to the wavelength, on the angle at which radiation strikes, and on the wavelength itself. 'Type of EM radiation' is not a separate factor in the standard list. So option D is the expected answer.

Why the other options are wrong

A: Roughness decides specular or diffuse reflection. B: Angle of incidence changes the amount and direction of reflection. C: Wavelength decides whether a surface behaves smooth or rough and changes reflectance.

Shortcut

Remember the standard three: roughness, angle, wavelength.

Common mistake

Thinking 'type of radiation' is different from wavelength. It is really described by wavelength.