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

This question tests whether we can connect ridging, albedo and radiation absorption correctly, since the assertion mixes these ideas up.

1. Assertion: It says ridging raises the albedo and that this raised albedo is what raises effective incoming radiation. This is backwards physics, since a higher albedo means more reflection and less absorption, not more. In reality, the ridge and furrow shape traps reflected light between the slopes, which lowers albedo rather than raising it, so the assertion is false.
2. Reason: It says tillage causes an uneven spread of energy at the surface. Since ridges expose sunlit and shaded faces at different angles to the sun, the surface really does receive and absorb energy unevenly, so this statement is true on its own.

Because the assertion itself does not hold up, the true reason cannot be explaining it, even though the reason is a correct fact by itself.

Let's summarize:

• Higher albedo means less absorption, so the assertion's logic is reversed.
• Ridged surfaces usually show lower albedo because of radiation trapping between ridges and furrows.
• The reason about uneven energy distribution is true but stands apart from the false assertion.

So the assertion is false while the reason is true, which is option 4.