Assertion (A): In Remote Sensing, the "Atmospheric Window" refers to the parts of the electromagnetic spectrum that are not significantly absorbed or scattered by the atmosphere. Reason (R): Thermal infrared sensors typically operate in the 8.0 to 14.0 µm range because the atmosphere is highly transparent in this band. Choose the correct option: (A) Both (A) and (R) are correct and (R) is the correct explanation of
- ABoth (A) and (R) are correct and (R) is the correct explanation of (A)Correct
- BBoth (A) and (R) are correct, but (R) is not the correct explanation of (A).
- C(A) is correct but (R) is incorrect.
- D(A) is incorrect but (R) is correct.
Solution
Concept
Atmospheric Window in Remote Sensing
Formula
N/A
Step-by-step solution
1. Understand Assertion (A) regarding atmospheric windows and Reason (R) regarding thermal infrared sensor ranges. 2. Verify that both statements are true, as atmospheric windows permit electromagnetic radiation to pass through, and thermal sensors utilize the transparent 8.0 to 14.0 µm band. 3. Confirm that Reason (R) directly explains Assertion (A) and select Option (A) as the correct choice.
Explanation
An atmospheric window is a range of wavelengths where light or heat passes through the atmosphere without being blocked or absorbed. Thermal infrared sensors use the 8.0 to 14.0 µm band specifically because it falls in one of these clear atmospheric windows. Since Reason (R) gives a direct example that demonstrates what an atmospheric window is and why it is used, both statements are true and (R) correctly explains (A).
Shortcut
To easily remember Atmospheric Windows and Thermal IR: - Atmospheric Window = Clear View: Portions of the spectrum where the atmosphere is completely transparent and does not block radiation. - Thermal IR Band (8–14 µm): Think "8 to 14 = Clear Heat": Thermal sensors specifically use this range because the atmospheric window is wide open for heat signals to pass through.
Common mistake
A common mistake is selecting Option B by assuming that while both statements are true, the Reason is merely an independent fact rather than the correct explanation. Students often fail to recognize that the thermal infrared band (8.0–14.0 µm) serves as a direct, practical application of an atmospheric window, making Reason (R) the true justification for Assertion (A).
Correct answer: A) Both (A) and (R) are correct and (R) is the correct explanation of (A)