पृथ्वी के वायुमंडल के संदर्भ में, निम्नलिखित कथनों में से कौन-सा एक सही है?
Read this question in English
With reference to the Earth's atmosphere, which one of the following statements is correct?
(a) The total amount of insolation received at the equator is roughly about 10 times of that received at the poles. · (b) Infrared rays constitute roughly two-thirds of insolation. · (c) Infrared waves are largely absorbed by water vapour that is concentrated in the lower atmosphere. · (d) Infrared waves are a part of visible spectrum of electromagnetic waves of solar radiation.
उत्तर और व्याख्या · explanation in English
Answer: (c) अवरक्त तरंगें निचले वायुमंडल में संकेंद्रित जलवाष्प द्वारा वृहद् रूप से अवशोषित होती हैं।
Statement (c) is correct: water vapour, ozone and other gases in the lower atmosphere (the troposphere) absorb much of the near-infrared radiation passing through. The other options misstate insolation values or the nature of infrared light.
- ✓ (c) NCERT says water vapour, ozone and other gases within the troposphere absorb much of the near-infrared radiation. Water vapour is concentrated in the lower atmosphere.
- ✗ (a) NCERT gives insolation at the surface as about 320 W/m2 in the tropics and about 70 W/m2 at the poles, a ratio of under five, and it says the equator receives less than the tropics. Ten times is far too high.
- ✗ (d) Infrared waves lie just beyond the visible spectrum; the human eye cannot see them. They are not part of the visible spectrum.
Remember · In the troposphere, water vapour, ozone and other gases absorb much of the near-infrared radiation. Insolation is about 320 W/m2 in the tropics and 70 W/m2 at the poles.
📘 Read it in NCERT: Class 11 Fundamentals of Physical Geography, Ch 8 (practise this chapter) · Class 11 Fundamentals of Physical Geography, Ch 8 (practise this chapter)
Sources
- NCERT Class 11 · Fundamentals of Physical Geography, Chapter 8 “Within the troposphere water vapour, ozone and other gases absorb much of the near infrared radiation.”
- NCERT Class 11 · Fundamentals of Physical Geography, Chapter 8 “The insolation received at the surface varies from about 320 Watt/m2 in the tropics to about 70 Watt/m2 in the poles.”
- Infrared Waves (NASA Science, Electromagnetic Spectrum) ↗ “the human eye cannot see it, but humans can detect it as heat. A remote control uses light waves just beyond the visible spectrum of light—infrared light waves—to change channels on your TV.”
Question and answer: UPSC's official GS Paper I (2023, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·