Question

Given below are two statements, one labelled as Assertion (A) and other one labelled as Reason (R).

Assertion (A): Ridging increases albedo, thereby increasing the effective incoming radiation compared to a flat surface.

Reason (R): Tillage causes unequal distribution of energy at the soil surface.

In light of the above statements, choose the correct answer from the options given below.

• A. Both (A) and (R) are true and (R) is the correct explanation of (A).
• B. Both (A) and (R) are true but (R) is NOT the correct explanation of (A).
• C. (A) is true but (R) is false.
• D. (A) is false but (R) is true.

Hint:

Remember that a rise in albedo means more reflection, not more absorption.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
The Assertion claims that ridging raises albedo and that this raised albedo is what increases the effective incoming radiation reaching the soil, compared with a flat field. The Reason claims tillage spreads energy unevenly across the surface. We need to check both and see if the Reason actually explains the Assertion.

Step 2: Key Formula or Approach:
Albedo is the fraction of incoming radiation that a surface reflects away rather than absorbs. A higher albedo means more radiation is bounced back and less is absorbed by the surface, not more. So any claim that a rise in albedo is what causes more radiation to be absorbed is backwards.

Step 3: Detailed Explanation:
When a field is ridged, the sloped ridge faces and the furrows create an uneven surface instead of a flat one. Sunlight that reflects off one sloped face can strike a neighbouring ridge or furrow wall instead of escaping straight back to the sky, so ridged fields typically trap more radiation and actually show a lower albedo than a flat field, not a higher one. The Assertion gets this backwards by saying albedo goes up and using that rise to explain the extra absorbed radiation, so the Assertion is false.
The Reason, however, is a separate and true fact on its own: because ridges and furrows face the sun at different angles, one side sunlit and the other shaded, tillage that creates this ridge and furrow shape does cause an uneven spread of incoming energy across the soil surface.

Step 4: Final Answer:
The Assertion is false while the Reason is true, matching option 4.