Question map
Not attempted Correct Incorrect ★ Bookmarked
Loading…
Q1 (IAS/2024) Geography › World Physical Geography › Atmospheric heat balance Official Key

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 ?

Result
Your answer: —  ·  Correct: D
Explanation

The correct answer is option D because Statement-I is incorrect while Statement-II is correct.

The bulk of the incoming solar radiation is absorbed by the Earth's surface, not[1] by the atmosphere[2]. The atmosphere transmits the incoming solar radiation but absorbs the vast majority of long wave radiation emitted upwards by the earth's surface[3]. This means the atmosphere is heated MORE by terrestrial (longwave) radiation than by incoming solar radiation, making Statement-I incorrect.

Statement-II is correct because carbon dioxide is transparent to the incoming solar radiation but opaque to the outgoing terrestrial radiation, and it absorbs a part of terrestrial radiation and reflects back some part of it towards the earth's surface[4]. Greenhouse gases in the atmosphere absorb much of the infrared energy emitted from the Earth's surface, preventing it from escaping, and then re-emit this energy in all directions, warming the Earth's surface and lower atmosphere[5].

Therefore, Statement-I is incorrect but Statement-II is correct, making option D the right answer.

Sources
  1. [1] https://www.ipcc.ch/site/assets/uploads/2018/02/ar4-wg1-faqs-1.pdf
  2. [2] https://www.ipcc.ch/site/assets/uploads/2018/03/ipcc_far_wg_I_full_report.pdf
  3. [3] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 11: World Climate and Climate Change > Global Warming > p. 96
  4. [4] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 7: Composition and Structure of Atmosphere > Gases > p. 64
  5. [5] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 17: Climate Change > Role of Greenhouse Gases > p. 255
How others answered
Each bar shows the % of students who chose that option. Green bar = correct answer, blue outline = your choice.
Community Performance
Out of everyone who attempted this question.
51%
got it right
PROVENANCE & STUDY PATTERN
Guest preview
Don’t just practise – reverse-engineer the question. This panel shows where this PYQ came from (books / web), how the examiner broke it into hidden statements, and which nearby micro-concepts you were supposed to learn from it. Treat it like an autopsy of the question: what might have triggered it, which exact lines in the book matter, and what linked ideas you should carry forward to future questions.
Q. Consider the following statements : Statement-I : The atmosphere is heated more by incoming solar radiation than by terrestrial radiati…
At a glance
Origin: Books + Current Affairs Fairness: Low / Borderline fairness Books / CA: 3.3/10 · 6.7/10
You're seeing a guest preview. The Verdict and first statement analysis are open. Login with Google to unlock all tabs.

This is a classic 'First Principles' Geography question directly from NCERT Class XI. It tests the fundamental physics of the Greenhouse Effect (Shortwave In vs. Longwave Out). If you understand why temperature decreases with height (Lapse Rate), you know the heat source is the ground, not the sun directly.

How this question is built

This question can be broken into the following sub-statements. Tap a statement sentence to jump into its detailed analysis.

Statement 1
Is Earth's atmosphere heated more by incoming solar (shortwave) radiation than by terrestrial (longwave) radiation?
Origin: Web / Current Affairs Fairness: CA heavy Web-answerable

Web source
Presence: 5/5
"Outgoing Longwave Radiation 235 Wm−2 Incoming Solar Radiation 342 Wm−2 ... Absorbed by Atmosphere ... Back Radiation 390 Surface Radiation 350"
Why this source?
  • Provides an energy-budget style breakdown with magnitudes showing atmospheric absorption of solar vs. large longwave exchanges (e.g., back radiation).
  • Shows back radiation (~390 W/m2) and surface longwave fluxes are large compared with direct atmospheric solar absorption values in the same budget.
Web source
Presence: 5/5
"About half of the incoming solar radiation is absorbed by the Earth’s surface. This energy is transferred to the atmosphere by warming the air in contact with the surface (thermals), by ­evapotranspiration and by longwave radiation that is absorbed by clouds and greenhouse gases."
Why this source?
  • States that about half of incoming solar is absorbed by the surface rather than directly by the atmosphere.
  • Explains that the atmosphere is heated by energy transferred from the surface (thermals, evapotranspiration) and by longwave radiation absorbed by clouds and greenhouse gases.
Web source
Presence: 4/5
"The bulk of the incoming solar radiation is absorbed not by the atmosphere but by the Earth's surface (soil, ocean, ice)"
Why this source?
  • Explicitly states that the bulk of incoming solar radiation is absorbed by the Earth's surface, not the atmosphere.
  • Implies the atmosphere's heating is largely driven by surface-absorbed solar energy being redistributed rather than direct shortwave absorption by the atmosphere.

FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 8: Solar Radiation, Heat Balance and Temperature > The Passage of Solar Radiation through the Atmosphere > p. 68
Strength: 5/5
“The atmosphere is largely transparent to short wave solar radiation. The incoming solar radiation passes through the atmosphere before striking the earth's surface. Within the troposphere water vapour, ozone and other gases absorb much of the near infrared radiation. Very small-suspended particles in the troposphere scatter visible spectrum both to the space and towards the earth surface. This process adds colour to the sky. The red colour of the rising and the setting sun and the blue colour of the sky are the result of scattering of light within the atmosphere.”
Why relevant

States the atmosphere is largely transparent to incoming shortwave solar radiation, with most solar reaching the surface (some near‑IR/water vapour absorption and scattering occur).

How to extend

A student could combine this with the fact that if most shortwave reaches the surface, then direct atmospheric heating from shortwave is limited compared to surface absorption.

FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 8: Solar Radiation, Heat Balance and Temperature > Terrestrial Radiation > p. 69
Strength: 5/5
“earth after being heated itself becomes a radiating body and it radiates energy to the atmosphere in long wave form. This energy heats up the atmosphere from below. This process is known as terrestrial radiation. The long wave radiation is absorbed by the atmospheric gases particularly by carbon dioxide and the other green house gases. Thus, the atmosphere is indirectly heated by the earth's radiation. The atmosphere in turn radiates and transmits heat to the space. Finally the amount of heat received from the sun is returned to space, thereby maintaining constant temperature at the earth's surface and in the atmosphere.”
Why relevant

Explains that the warmed Earth radiates longwave energy upward and that this terrestrial longwave is absorbed by greenhouse gases, heating the atmosphere from below.

How to extend

Combine with estimates of surface emission (from surface temperature) to infer the magnitude of longwave energy available to heat the atmosphere.

Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 22: Vertical Distribution of Temperature > 22.2. Lapse Rate > p. 295
Strength: 4/5
“Hence, the lapse rate of the troposphere below tropopause is positive, the lapse rate of the tropopause is zero, and the lapse rate of the stratosphere is negative.• The fall in temperature with altitude is primarily due to the following reason: • Atmosphere is mostly transparent to the incoming shortwave radiation but actively absorbs the outgoing terrestrial (longwave) radiation.• Greenhouse house gases like CO2, and water vapour, are the primary absorbers of terrestrial radiation and their concentration is highest at the earth's surface and goes on decreasing with altitude. Hence, the temperature falls with altitude (elevation).• The lapse rate of non-rising air (environmental lapse rate) is highly variable, being affected by radiation, convection, condensation and concentration of greenhouse gases.”
Why relevant

Gives the general rule: atmosphere is mostly transparent to incoming shortwave but actively absorbs outgoing terrestrial longwave; links this to temperature lapse rate.

How to extend

Use this rule plus the vertical distribution of greenhouse gases (concentrated near surface) to argue that absorbed longwave dominates near‑surface atmospheric heating.

FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 11: World Climate and Climate Change > Global Warming > p. 96
Strength: 4/5
“Due to the presence of greenhouse gases, the atmosphere is behaving like a greenhouse. The atmosphere also transmits the incoming solar radiation but absorbs the vast majority of long wave radiation emitted upwards by the earth's surface. The gases that absorb long wave radiation are called greenhouse gases. The processes that warm the atmosphere are often collectively referred to as the greenhouse effect. The term greenhouse is derived from the analogy to a greenhouse used in cold areas for preserving heat. A greenhouse is made up of glass. The glass which is transparent to incoming short wave solar radiation is opaque to outgoing long wave radiation.”
Why relevant

Summarises the greenhouse effect: atmosphere transmits incoming solar but absorbs the vast majority of longwave emitted by the surface.

How to extend

A student could take this qualitative ‘vast majority’ claim and compare it to known solar fluxes (insolation) to judge which flux heats the atmosphere more.

Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 1: BASIC CONCEPTS OF ENVIRONMENT AND ECOLOGY > Structure of the Atmosphere > p. 8
Strength: 3/5
“Te upper boundary of this layer is called the mesopause.• 4. Termosphere (Heat Sphere): Tis sphere extends from 80 to 480 kms in altitude. In thermosphere, temperatures increase with height. High temperatures are generated in the thermosphere because the gas molecules absorb shortwave solar radiation. Te temperature curve in Fig. 1.2 shows that temperature rises sharply in the thermosphere, up to 1200°C and higher. Despite such high temperatures, the thermosphere is not 'hot' in the way one might expect. Temperature and heat are two diferent things. Te intense solar radiation in this portion of the atmosphere excites individual molecules and atoms (principally nitrogen and oxygen).”
Why relevant

Shows an important exception: high-altitude thermosphere absorbs shortwave solar radiation strongly, producing high temperatures aloft.

How to extend

Combine this with knowledge of atmospheric mass/energy distribution to note that shortwave heating can dominate in upper layers while longwave heating dominates the lower atmosphere.

Statement analysis

This statement analysis shows book citations, web sources and indirect clues. The first statement (S1) is open for preview.

Login with Google to unlock all statements.

Statement analysis

This statement analysis shows book citations, web sources and indirect clues. The first statement (S1) is open for preview.

Login with Google to unlock all statements.

How to study

This tab shows concrete study steps: what to underline in books, how to map current affairs, and how to prepare for similar questions.

Login with Google to unlock study guidance.

Micro-concepts

Discover the small, exam-centric ideas hidden in this question and where they appear in your books and notes.

Login with Google to unlock micro-concepts.

The Vault

Access hidden traps, elimination shortcuts, and Mains connections that give you an edge on every question.

Login with Google to unlock The Vault.

✓ Thank you! We'll review this.

SIMILAR QUESTIONS

IAS · 2023 · Q64 Relevance score: 3.69

Consider the following statements : Statement-I : The temperature contrast between continents and oceans is greater during summer than in winter. Statement-II : The specific heat of water is more than that of land surface. Which one of the following is correct in respect of the above statements?

IAS · 2025 · Q26 Relevance score: 3.36

Consider the following statements : Statement I : The amount of dust particles in the atmosphere is more in subtropical and temperate areas than in equatorial and polar regions. Statement II : Subtropical and temperate areas have less dry winds. Which one of the following is correct in respect of the above statements?

IAS · 2025 · Q29 Relevance score: 3.22

Consider the following statements : I. Without the atmosphere, temperature would be well below freezing point everywhere on the Earth's surface. II. Heat absorbed and trapped by the atmosphere maintains our planet's average temperature. III. Atmosphere's gases, like carbon dioxide, are particularly good at absorbing and trapping radiation. Which of the statements given above are correct?

IAS · 2025 · Q33 Relevance score: 3.01

Consider the following statements : Statement I : Scientific studies suggest that a shift is taking place in the Earth's rotation and axis. Statement II : Solar flares and associated coronal mass ejections bombarded the Earth's outermost atmosphere with tremendous amount of energy. Statement III : As the Earth's polar ice melts, the water tends to move towards the equator. Which one of the following is correct in respect of the above statements?