CSE 2024 GS 1 Q1 – Atmosphere is Heated more by Terrestrial Radiation …

Question 1: Consider the following statements:

Statement-I: The atmosphere is heated more by incoming solar radiation than by terrestrial radiation.

Statement-II: Carbon dioxide and other greenhouse gases in the atmosphere are good absorbers of long wave radiation.

Which one of the following is correct in respect of the above statements?

(a) Both Statement-I and Statement-II are correct and Statement-II explains Statement-I

(b) Both Statement-I and Statement-II are correct, but Statement-II does not explain Statement-I

(c) Statement-I is correct, but Statement-II is incorrect

(d) Statement-I is incorrect, but Statement-II is correct

प्रश्न 1: निम्नलिखित कथनों पर विचार कीजिए:

कथन-I:पार्थिव विकिरण की तुलना में आगामी (इनकमिंग) सौर विकिरण से वायुमंडल अधिक गर्म हो जाता है।

कथन-II:वायुमंडल में कार्बन डाइऑक्साइड और अन्य ग्रीनहाउस गैसें दीर्घ तरंग विकिरण के अच्छे अवशोषक हैं।

उपर्युक्त कथनों के संबंध में, निम्नलिखित में से कौन-सा सही है?

(a)कथन-I और कथन-II दोनों सही हैं तथा कथन-II, कथन-I की व्याख्या करता है

(b)कथन-I और कथन-II दोनों सही हैं, किन्तु कथन-II, कथन-I की व्याख्यानहींकरता है

(c)कथन-I सही है, किन्तु कथन-II सही नहीं है

(d)कथन-I सही नहीं है, किन्तु कथन-II सही है

Answer

(d) Statement-I is incorrect, but Statement-II is correct

Subject & Topic

Geography – Atmosphere

Explanation

This question is directly from the Class XI – NCERT Geography – Fundamentals of Physical Geography – Chapter 8: Solar Radiation, Heat Balance and Temperature.

Image Source / Copyright: Pearson Prentice Hall, Inc.

Consider that the insolation received at the top of the atmosphere is 100 per cent. While passing through the atmosphere some amount of energy is reflected, scattered, and absorbed. Only the remaining part reaches the earth surface. Roughly 35 units are reflected back to space even before reaching the earth’s surface. Of these, 27 units are reflected back from the top of the clouds and 2 units from the snow and ice-covered areas of the earth. The reflected amount of radiation is called thealbedo of the earth.

The remaining 65 units are absorbed, 14 units within the atmosphere and 51 units by the earth’s surface. The earth radiates back 51 units in the form of terrestrial radiation. Of these, 17 units are radiated to space directly and the remaining 34 units are absorbed by the atmosphere (6 units absorbed directly by the atmosphere, 9 units through convection and turbulence and 19 units through latent heat of condensation).

48 units absorbed by the atmosphere (14 units from insolation +34 units from terrestrial radiation) are also radiated back into space. Thus, the total radiation returning from the earth and the atmosphere respectively is 17+48=65 units which balance the total of 65 units received from the sun. This is termed the heat budget or heat balance of the earth.

Thus, the atmosphere is heated more by terrestrial radiation than by incoming solar radiation.

Therefore, Statement I is incorrect.

Long-wave radiation is absorbed by atmospheric gases, particularly carbon dioxide and other greenhouse gases, as they are good absorbents of long-wave radiation.

Therefore, Statement II is correct.

Source(s)

NCERT Class 11 Geography Book – Fundamentals of Physical Geography – Chapter 8 Solar Radiation, Heat Balance and Temperature

Difficulty level

Easy as straight forward from NCERT Textbook