Question

Given below are two statements:
Statement (I): The greenhouse effect is retention of heat in the lower atmosphere due to absorption and re-radiation by clouds and certain gases.
Statement (II): Long-wave thermal solar radiation received from the sun passes through the atmosphere with little or no interference and warms the earth's surface.
In light of the above statements, choose the most appropriate answer from the options given below.

• A. Both Statement (I) and Statement (II) are correct.
• B. Both Statement (I) and Statement (II) are incorrect.
• C. Statement (I) is correct but Statement (II) is incorrect.
• D. Statement (I) is incorrect but Statement (II) is correct.

Hint:

Incoming solar radiation is high-energy, short-wave radiation, which passes through greenhouse gases easily.
Outgoing terrestrial radiation is low-energy, long-wave thermal radiation, which is absorbed and re-radiated by greenhouse gases, creating the warming effect.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The global energy balance of the Earth is regulated by incoming solar radiation (short-wave) and outgoing terrestrial radiation (long-wave).
The atmospheric greenhouse effect plays a critical role in maintaining global temperatures within a range suitable for life.

Step 2: Detailed Explanation:
Let us evaluate each of the given statements:
- Statement (I): The greenhouse effect is a natural atmospheric process.
The Earth's surface absorbs incoming solar energy and re-radiates it upward as long-wave infrared radiation.
Greenhouse gases (such as water vapor, carbon dioxide, methane, and nitrous oxide) and clouds absorb a portion of this outgoing long-wave radiation rather than letting it escape directly into space.
These gases then re-radiate this absorbed heat in all directions, including back toward the Earth's surface, warming the lower atmosphere.
Therefore, Statement (I) is correct.
- Statement (II): Solar radiation emitted by the Sun is high-energy, short-wave radiation (not long-wave thermal radiation).
This incoming short-wave radiation passes through the atmosphere with relatively little absorption by atmospheric gases, reaching and warming the Earth's surface.
The Earth's surface then converts this energy and emits it back as long-wave thermal infrared radiation.
Therefore, Statement (II) is incorrect because it falsely labels solar radiation as long-wave thermal radiation.
Since Statement (I) is correct and Statement (II) is incorrect, option (C) is the correct choice.

Step 2: Final Answer:
Statement (I) is correct but Statement (II) is incorrect.